Twenty

Words for twenty and related things in Celtic languages:

twenty

Proto-Celtic *wikantī = twenty
Gaulish uoconti = twenty
Old Irish (Goídelc) fiche [ˈfʲixʲe] = twenty
fichetmad = twentieth
fichtige = twenty day/year period
Middle Irish (Gaoidhealg) fiche, fichet, fichit, fichtea = twenty, a score
fichetmad, fichatmath, fichetmudh = twentieth
fichetech = pertaining to twenty
fichtige = a period of twenty (days, years, etc)
Irish (Gaeilge) fiche [ˈfʲɪhə/ˈfʲɪçə/fʲiː] = twenty
(an) fichiú = twentieth
Scottish Gaelic (Gàidhlig) fichead [fiçəd] = twenty, a score
ficheadamh [fiçədəv] (20ᵐʰ) = twentieth (20ᵗʰ)
fichead-shliosnach = icosahedron (a polyhedron with 20 faces)
fichead-fillte = twentyfold
Manx (Gaelg) feed [fiːdʒ] = twenty, a score
feedoo, (yn) eedoo = (the) twentieth
feed cheead = two thousand (twenty hundred)
Proto-Brythonic *ʉgėnt = twenty
Cumbric giggy, jiggit = twenty
Old Welsh uceint = twenty
Middle Welsh (Kymraec) ugein, ugeint, vgein = twenty
vgeinvet, ugeinuet = twentieth
ugeinwyr, vgainwyr, vgain-wr, vgain-ŵr = twenty men
Welsh (Cymraeg) ugain [ˈɪɡai̯n/ˈiːɡai̯n] = twenty, score, twenty-pound note
ugeinfed [ɪˈɡei̯nvɛd] (20fed) = twentieth
ugeiniol = pertaining to twenty, denoting twenty
ugeinw(y)r = twenty men
Middle Cornish (Cernewec) ugans, hugens = twenty, a score
Cornish (Kernewek) ugens, ugans = twenty
ugensves = twentieth
Old Breton ucent = twenty
Middle Breton (Brezonec) vgent, uiguent, ugent = twenty
ugentved = twentieth
ugentvedenn = twentieth part
ugentad = around twenty
ugentvedenni, ugentvedenna = to divide by twenty
ugentveder = a commemoration of 20 years
ugentvederel = vigesimal (20-base numeral system)
Breton (Brezhoneg) ugent [ˈyːɡẽn(t)] = twenty
ugentvet = twentieth
ugentvedenn = twentieth part
ugentad = around twenty

Etymology: from Proto-Indo-European *dwi(h₁)dḱm̥ti (twenty) from *wídḱm̥ti (twenty) [source].

Words from the same roots include بیست‎ (bist – twenty) in Persian (Farsi), बीस (bīs – twenty) in Hindi and Nepali, বিশ (biś – twenty) in Bengali and વીસ (vīs – twenty) in Gujarati, and words for twenty in some other Indo-European languages languages [source].

Incidentally, the English words twenty, and words for twenty in other Germanic languages, are not cognate. Instead they come from the Proto-Germanic roots *twain- (two) ‎and *-tigaz (group of ten) [source].

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Spears and Javelins

Words for spear, javelin and related things in Celtic languages:

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Proto-Celtic *gaisos = spear
Gaulish *gaisos = spear
*Ariogaisos = male given name
Old Irish (Goídelc) gae [ɡai̯] = javelin, spear, penis
gae cró = gush of blood, haemorrhage, unhealed wound
gae gréne = sunbeam
Middle Irish (Gaoidhealg) gae, ga = spear, javelin; ray, beam
ga-ín = little javelin
gaíde = armed with a spear
Irish (Gaeilge) ga [ɡa/ɡaː/ɡah] = spear, dart, sting, ray (of light), radius, suppository, (fishing) gaff
ga-chatóideach = cathode ray
ga-gréine = sunbeam
ga-gealaí = moonbeam
ga-shiméadracht = radial symmetry
gáma-gha = gamma ray
X-gha = X-ray
Scottish Gaelic (Gàidhlig) gath [ɡah] = dart, beam, ray (of light), sting, barb, knot (in wood), shooting pain, sprout
gath-gealaich, gath-luain = moonbeam
gath-grèine = sunbeam
gath-leusair = laser beam
gath-x, gath-òmair = X-ray
gath cathod = cathode ray
gath-solais = ray of light, light beam
Manx (Gaelg) goull = beam, dart, ray
goull eayst = moonbeam
Middle Welsh (Kymraec) guaew, gvoev, gwaew, gwayw = lance, spear, javelin
gwaewdwnn = with broken spear, bold, broken by pain
gwaew ffon, gwaiw ffon = speak, lance, javelin, pike
Welsh (Cymraeg) gwayw [ɡweɨ̯.ʊ/ˈɡwei̯.u] = lance, spear, javelin; shooting pain, stab, stitch, pang
gwaywawr, gwaywor = spearman, lancer, pikeman
gwaywdwn = with broken spear, bold, broken by pain
gwayw-fwyell = halberd
gwaywffon [ˈɡweɨ̯wfɔn/ˈɡwei̯wfɔn] = speak, lance, javelin, pike
Old Cornish (hoch-)wuyu = spear
Middle Cornish (Cernewec) guw = spear. lance, javelin
Cornish (Kernewek) guw = spear
guwa = to spear
Old Breton (guu)goiou = spear
Middle Breton (Brezonec) goaff, goaf, goao, gwaf = spear, stamen, boat hook
Breton (Brezhoneg) goaf = spear, pike, javelin, stamen

Etymology: from Proto-Germanic *gaizaz [ˈɣɑi̯.zɑz] (spear, pike, javelin), from Proto-Indo-European *ǵʰoysós (throwing spear), from *ǵʰey- (to throw, impel) [source].

Words from the same Proto-Celtic root include gezi [ɡe̞.s̻i] (arrow) in Basque (via Latin and Gaulish), գայիսոն [ɡɑjiˈsɔn/kʰɑjiˈsɔn] (sceptre) in Armenian (via Ancient Greek), gaesum (a Gaulish javelin) in Latin, and γαῖσος [ɡâi̯.sos] (a Gaulish javelin) in Ancient Greek [source].

Words from the same Proto-Germanic root include garfish (any fish of the needlefish family Belonidae) in English [source], geer (spear) in Dutch, Ger (spear) in German, geir (spear) in Icelandic, keihäs (spear, javelin, pike) in Finnish, [source].

My surname, Ager, possibly comes from the same Proto-Germanic root as well, via the Old English name Ēadgār, from ēad (happiness, prosperity), and gār (spear) [source].

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Nine

Words for nine and related things in Celtic languages:

nine

Proto-Celtic *nowan = nine
*naumetos = ninth
Gaulish *nau = nine
nametos = ninth
Old Irish (Goídelc) noí [n͈oːi̯] = nine
nómad = ninth
nónbor = nine people
noínden = nine days
Middle Irish (Gaoidhealg) noí, noi = nine
nómad, nomad = ninth
nónbor = nine people
noínden = nine days
noíchtige = a period of 29 days
nócha, nocha, nochat = ninety
Irish (Gaeilge) naoi [n̪ˠiː/n̪ˠɰiː] = nine
(an) naoú = ninth
naonúr = nine people
naoi déag = nineteen
nócha = ninety
naoichodach = ninefold, having nine parts
Scottish Gaelic (Gàidhlig) naoi(dh) [n̪ˠɯj] = nine
naodh [n̪ˠɯːɣ] = nine
naoitheamh [n̪ˠɤjəv] (9ᵐʰ) = ninth (9ᵗʰ)
naoinear [n̪ˠɯːn̪ʲər] = nine (people)
naoi deug = nineteen
naochad [n̪ˠɯːxəd] = ninety
naoidh-fillte = nonuple, ninefold, nine-ply
Manx (Gaelg) nuy [nɛi/niː] = nine
(yn) nuyoo = (the) ninth
nuy jeig = nineteen
nuy-cheayrtyn, nuy-filley = ninefold
nuy-uillinagh = nonagonal, nonagon
Proto-Brythonic *naw [n͈oːi̯] = nine
*nọβ̃ed = ninth
Old Welsh naw = nine
Middle Welsh (Kymraec) nav, nau, naw = nine
navuet, nauuet, nawued, nawuet = ninth
naw deg, naw-deg = ninety
nawkan, naw cant, nawcant = nine hundred, many, numerous
naw ugein(t) = 180
nawbann, nowban = (having) nine syllables (in Welsh poetry)
nawwell, nawell = nine times better (than), much better
naun, nawn, naon = the ninth hour of the day
naw nyn, nawnyn = nine men
Welsh (Cymraeg) naw [naːu̯/nau̯] = nine
nawfed [ˈnau̯vɛd/ˈnau̯vad] (9fed) = ninth, one of nine, nones (in Roman calendar)
deunaw = eighteen (two nines)
naw deg = ninety
nawcant = nine hundred, many, numerous
nawban, naw ban = (having) nine syllables (in Welsh poetry)
nawell = nine times better (than), much better
nawn = the ninth hour of the day (approx. 3pm) midday, nooon, afternoon
nawnbryd = evening meal, dinner, supper
nawnyn, naw nyn = nine men
nawplyg = ninefold
Middle Cornish (Cernewec) naw = nine
nawnzac, nawntek, nownsec, nowndzhak = nineteen
naiv cans = nine hundred
Cornish (Kernewek) naw = nine
nawves = ninth
nownsek = nineteen
nowsegves = nineteenth
Old Breton nau = nine
Middle Breton (Brezonec) nau, nao, naou, naff, nauë, naü = nine
navet = ninth
nauntec, nantec, nandec = nineteen
naontecvet, nandecvèd, naontekved, naoñteget = nineteenth
nao ugent = 180
Breton (Brezhoneg) nav [ˈnaw] = nine
navet = ninth
naontek = nineteen

Etymology: from Proto-Indo-European *h₁néwn̥ (nine) and *h₁newn̥nós (ninth) [source].

English words from the same roots include nine, and words beginning with ennea-, such as enneagon (a 9-sided polygon) and enneastyle (having 9 columns) [source].

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Eightsome

Words for eight and related things in Celtic languages:

eight

Proto-Celtic *oxtū = eight
*oxtūmetos = eighth
Old Irish (Goídelc) ocht [ˈoxt] = eight
ochtmad [ˈoxtṽað] = eighth
ochtar = a group of eight people
ochtmoga = eighty
Middle Irish (Gaoidhealg) ocht = eight
ochtmad = eighth
ochtur, ochtor, ochtar = eight people/things
ochta = a group of eight things, an octad
ochtmoga, ochtmogo, ochtmogat = eighty
Irish (Gaeilge) ocht [ɔxt̪ˠ/ʌxt̪ˠ]= eight
ochtar = eight (people)
ochtú = eighth, eighth part
ocht déag = eighteen
ochtó = eighty
ochtddach = having eight parts, eightfold
ochtábhó = octavo
ochtach, ochtáibh = octave
ochtagán = octagon
ochtapas = octopus
Scottish Gaelic (Gàidhlig) ochd [ɔxg] = eight
ochdamh [ɔxgəv] (8ᵐʰ) = eighth (8ᵗʰ)
ochdnar [ɔxgnər] = eight people
ochd-fillte = octuple, eightfold, eight-ply
ochd-shliosach = octagon, octahedron
ochd-chasach = octopus
Manx (Gaelg) hoght [hoːx(t)] = eight, octuple
hoghtoo = eighth
hoght jeig = eighteen
hoghtad = eighty
hoght filley, hoght keayrtyn = eightfold
oght-lhiatteeane, hoghtin = octagon
hoght lhiatteeagh = octagonal
hoght-choshagh = octopus
Gaulish oxtu = eight
oxtumetos = eighth
Proto-Brythonic *üiθ [yɨ̯θ] = eight
*üɨθβ̃ed = eighth
Cumbric owera, hovera, haoves = eight
Old Welsh oith = eight
Middle Welsh (Kymraec) uith, wyth, vyth, ỽyth, oeth [sei̯θ] = eight
wythuet, wythued, ỽythuet = eighth
wythnos, vythnos, ỽythnos = week
petheunos, pytheonos, pethawnos = fortnight (two weeks)
Welsh (Cymraeg) wyth [uːɨ̯θ/ʊi̯θ] = eight, octave,
wythfed (8fed) [ˈʊɨ̯θvɛd/ˈʊi̯θvɛd] = eighth, one of eight
wyth deg = eighty
wythdegai = eighties
wythawd = octet, octave
wythblyg = octavo, eightfold, having eight parts
wythnyn = eight persons, eight men
wythochr = octahedron, octagon, octagonal
wythnos [ˈʊɨ̯θnɔs] = week
penwythnos = weekend
pythefnos = fortnight (two weeks)
Middle Cornish (Cernewec) eath = eight
eathas = eighth
eitag, eythek = eighteen
Cornish (Kernewek) eth = eight
ethves = eighth. octave
etek = eighteen
etegves = eighteenth
Old Breton (Brethonoc) eith = eight
Middle Breton (Brezonec) eiz = eight
eizuet, aihuet, eizved = eighth
eiz-ugeñt, heiz-ugent = 160
eiz-cognecq = octagonal
eiz-cornecq = octagonal, octagon
eizuet, aihuet, eizvet, eizved, eihvet = eighth
éih dyad, ein-déad, eih-diat = about eight
eizdezyeg, eizdeziek = weekly
eizvedi = to divide into eight
Breton (Brezhoneg) eizh = eight
eizhved = eighth
eikont = eighty (usually pevar-ugent)
eizhkognek = octagonal

Etymology: from Proto-Indo-European *oḱtṓw (eight) [source]. Words from the same PIE root include eight, and words beginning with octa-/octo-, such as October, octane and octopus in English, and words related to eight in other Indo-European languages [source].

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Sevenfold

Words for seven and related things in Celtic languages:

seven

Proto-Celtic *sextam = seven
*sextametos = seventh
Old Irish (Goídelc) secht [sʲext] = seven
sechtmad = seventh
sechtae = seven things
sechtmoga = seventy
sechtmain = week
Middle Irish (Gaoidhealg) secht [ɕext] = seven, seven times, seven things
sechtmad, sechtmet, ṡec[t]maid = seventh, one of seven; a period of seven days
sechtae, sechta = sevenfold, septenary, septenary
sechtmoga, sechtmogo, sechtmogat = seventy
sechtmain(e) = week
Irish (Gaeilge) seacht [ʃaxt̪ˠ/ʃæxt̪ˠ]= seven
seacht déag = seventeen
seachtú = seventh (7ᵗʰ), seventh part
seachtach = seventh (in music)
seachtain = week
seachtainiúil = weekly
seachtar = seven people/things
seachtó = seventy
seachtbhliantúil = septennial (a period or cycle of seven years)
seachtchodach = sevenfold
seachtfhillte = folded in seven, sevenfold
Scottish Gaelic (Gàidhlig) seachd [ʃɛxg] = seven
seachdamh [ʃɛxgəv] (7ᵐʰ) = seventh (7ᵗʰ)
seachdnar [ʃɛxgn̪ər] = seven people
seachd-fillte = sevenfold
seachd-shliosach [ʃesgəd] = heptagon(al)
seachd deug = seventeen
seachdad [ʃɛxgəd] = seventy, the 70s
seachdain [ʃɛxgɛn̪ʲ] = week
seachdaineil [ʃɛxgɪn̪ʲal] = weekly
deireadh-seachdain, ceann-seachdain = weekend
Na Seachd-Reultan = the Pleiades, the Seven Sisters
Manx (Gaelg) shiaght [ʃaːxt] = seven, septet
shiaghtoo, (yn) chiaghtoo = seventh
shiaght jeig = seventeen
shiaght jeigoo = seventeenth
shiaght filley = septuple, sevenfold
shiaghtin = week, heptagon
jerrey shiaghtin = weekend
Gaulish sextam = seven
sextametos = seventh
Proto-Brythonic *seiθ [sɛi̯θ] = seven
*seɨθβ̃ed [hwɛˈxɛːd] = seventh
Cumbric mithy, lethera, saites = seven
Middle Welsh (Kymraec) sseith, seith [sei̯θ] = seven
seithued, seythuet, seithuet = seventh
seith dyblyc, saith ddyblyg = sevenfold
seyth nyn, seyth dyn = seven persons, seven men
Welsh (Cymraeg) saith [sai̯θ] = seven, sevenpence
seithfed (7ed) [ˈsei̯θvɛd/ˈsei̯θvad] = seventh
saithdeg = seventy
saithdegau = seventies
saithdegfed = sevenieth
saithddyblyg = sevenfold
seithawd = a group of seven people or things, septet, seventh (in music)
seithblyg = sevenfold, septuple, have 7 parts or arms (candelabrum)
seithliw = seven colours, seven-coloured, iridescent
seithnyn = seven persons, seven men
seithochr = heptagon(al), septangular
Old Cornish syth = seven
Middle Cornish (Cernewec) seith, syth, sŷth = seven
seithvas, sythvas = seventh
seitag, seitek = seventeen
seithun, seithan, sythyn = week
Cornish (Kernewek) seyth [səiθ] = seven
seythves = seventh
seythen = week
seythennyek, seythednek = weekly
pennseythen = weekend
Old Breton (Brethonoc) seith = seven
Middle Breton (Brezonec) seiz, seyz = seven
seizuet, seizüet, seihuit, seizved = seventh
seizdec, seitec, seytecq, zeitec = seventeen
seitêcvèd, seitekved, zeiteget = seventeenth
sizun, syzun, sehun, siun = week
Breton (Brezhoneg) seizh [ˈxwɛx] = seven
seizhved = seventh
seitek = seventeen
seitegvet = seventeenth
sizhun = week

Etymology: from Proto-Indo-European *septḿ̥ (seven) [source]. Words from the same PIE root include seven, and words beginning with hepta-/sept(a/i)-, such as heptastyle (having 7 columns), septemplex (sevenfold), septasyllabic (having 7 syllables) and septilateral (having 7 sides) in English, and words related to seven in other Indo-European languages [source].

The Old Irish word sechtmain was borrowed from the Late Latin septimāna (week), from septimānus (related to the 7th element of a series), from the Latin septimus (7th) [source]. Words for week in Cornish and Breton probably came from the same roots.

A week in Welsh is wythnos (“8-night”), as weeks in Wales have an extra night. A weekend is penwythnos and a fortnight (2 weeks) is pythefnos (“15-night”).

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Merciful

Words for merciful and related things in Celtic languages.

Winter Sunshine

Proto-Celtic *trougokaros/*trowkkaro- = merciful
Old Irish (Goídelc) trócar = merciful
trócaire = mercy
Middle Irish (Gaedhealg) trócar, trócair, trocor = merciful, leniency
trócaire, trocaire = mercy, leniency, equity, piety
Irish (Gaeilge) trócaire [ˈt̪ˠɾˠoːkəɾʲə] = mercy, pity, compassion, clemency, leniency
trócaireach = merciful, clement, lenient, compassionate
Scottish Gaelic (Gàidhlig) tròcair [trɔːxgɪrʲ] = mercy, pity, pardon, quarter
tròcaireach [trɔːxgɪrʲəx] = merciful, compassionate
tròcaireachd [trɔːxgɪrʲəxg] = mercifulness, compassion
Manx (Gaelg) trocair = mercifulness, mercy, pity
trocairagh = clement, lenient, merciful
trocairaght = mercy
trocairys = affection, clemency, leniency, mercifulness, ruth
trocairaght = mercy
trochoil = lenient
trochoilys = leniency, mercifulness
Old Welsh trucarauc = merciful, compassionate, kind
Middle Welsh (Kymraec) trugar, trûgar = merciful, tender-hearted, compassionate
trugaret, trugared = mercy, compassion, pity
trigareddva = mercy-seat, throne (of God), mercy or reconcilliation
trugarha, trukarhaa = to have mercy (on), be kind (to) forgive
trugaraỽc, trugarock, trugaroc = merciful, compassionate, kind
Welsh (Cymraeg) trugar [ˈtrɨgar/ˈtrigar] = merciful, tender-hearted, compassionate
trugaredd = mercy, compassion, pity, tender-heartedness, kindness, humanity, good will; paraphernalia, bits and pieces, knick-knacks
trugareddfa = mercy-seat, throne (of God), mercy or reconcilliation
trugareddol, trugareddus = merciful, compassionate
trugarhaf, trugarhau = to have mercy (on), be kind (to) forgive
trugarog = merciful, compassionate, kind, tender-hearted, gentle, humane, forgiving
Middle Cornish (Cernewec) tregereth = compassion, pity, mercy, love
Cornish (Kernewek) tregeredh = compassion, mercy, sympathy
tregeredhus = sensitive, sympathetic
Old Breton trugar = pitiful, wretched, miserable
Middle Breton (Brezonec) trugar = pitiful, wretched, miserable
trugarez = pity, mercy, forgiveness, thanks, misery
Breton (Brezhoneg) trugarez = thank you, mercy, clemency, indulgence
trugarekaat = to thank, pity

Etymology: from Proto-Celtic *trougos/*trowgo- (sorry, sad, wretched) and *-karos (loving) [source].

Words marked with a * are reconstructions.

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Hexagonal

Words for six and related things in Celtic languages:

Six

Proto-Celtic *swexs = six
*suexos = sixth
Old Irish (Goídelc) [sʲeː] = six
seisser = six people
séda = six things
seissed [ˈsʲesʲeð] = sixth
sesca [ˈsʲeska] = sixty
Middle Irish (Gaoidhealg) sé, se, sē = six
seisser, seissiur, seissir = six people
seissed, sesset, sesedh, seisedh = sixth, one of six
sé déc = sixteen
sesca, sescot, sescat = sixty
Irish (Gaeilge) [ʃeː/ʃɛ/ʃə]= six
(an) seú = sixth
seisear = six people
sé déag = sixteen
seasca = sixty
Scottish Gaelic (Gàidhlig) sia [ʃia] = six
(an) siathamh [ʃiə.əv] (6ᵐʰ) = sixth (6ᵗʰ)
sianar [ʃianər] = six people
sia deug = sixteen
seasgad [ʃesgəd] = sixty
sia-cheàrnach = hexagon
Manx (Gaelg) shey = six, sextet
sheyoo, (yn) çheyoo = sixth
shey jeig = sixteen
shey jeigoo = sixteenth
shey keayrtyn = sextuple, six times
shey pingyn = sixpence
Gaulish suex = six
suexos = sixth
Proto-Brythonic *hwex [ˈhwɛːx] = six
*hwexed [hwɛˈxɛːd] = sixth
Cumbric sethera, hither = six
Old Welsh chwech = six
Middle Welsh (Kymraec) chwech, whech, whe, hwech, chwe = six
hhuechet, cchuehet, chwechet, whechet = sixth
Welsh (Cymraeg) chwech [χweːχ/hweːχ] = six, sixpence
chweched (6ed) [ˈχwɛχɛd/ˈχwɛχad] = sixth
chwedeg = sixty
chwedegfed = sixieth
chwechant = six hundred
chwecheiniog = sixpenny bit, sixpence
Middle Cornish (Cernewec) huih, hweh, whéh = six
hweffas, wheffes = sixth
whehdeg = sixteen
whehdegvas = sixteenth
Cornish (Kernewek) hwegh = six
hweghves, hweffes = sixth
hwetek = sixteen
hwetegves = sixteenth
hweghmis = semester
Old Breton (Brethonoc) chouech = six
Middle Breton (Brezonec) huech, huec, c’huec’h, chouech, hueh = six
huechuet, huehuet, c’huec’hved = sixth
c’huezec, c’houezek = sixteen
c’houezekved = sixteenth
Breton (Brezhoneg) c’hwec’h [ˈxwɛx] = six
c’hwec’hvet = sixth
c’hwezek = sixteen
c’hwezekvet = sixteenth
c’hwec’h-ugent = 120 (6*20)
c’hwec’h-kement = sextuple
c’hwec’h-kogn = hexagon
c’hwec’h-miz = semester

Etymology: from Proto-Indo-European swéḱs (six). Words from the same PIE root include six, sextuple, and words beginning with hex-, such as hexagon in English, and words for six in other Indo-European languages [source].

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Quintuple

Words for five and related things in Celtic languages:

five

Proto-Celtic *kʷenkʷe = five
*kʷenkʷetos = fifth
Old Irish (Goídelc) cóic [koːɡʲ] = five
cóiced [ˈkoːɡʲeð] = fifth
cóicer = five people, five things
coíca = fifty
Middle Irish (Gaoidhealg) cóic, cúic = five
cóiced, cúced, coigid = fifth
cóicer, cóicir, cuicir = five people/things
cóic deac = fifteen
coíca, coícad, cóic deich = fifty
Irish (Gaeilge) cúig [kuːɟ] = five
cúigiú [kuːˈɟuː/ˈkuːɟu] = fifth
cúigear [ˈkuːɟəɾˠ] = five people/things
cúige = one of five divisions of Ireland, province
caoga = fifty
cúigbhliantúil = five-yearly, quinquennial
cúigchodach = fivefold, quintuple
cúigréad = quintet
Scottish Gaelic (Gàidhlig) còig [koːgʲ] = five
còigeamh(5ᵐʰ) fifth (4ᵗʰ))
còignear [koːgʲn̪ʲər] = five (people)
còigearan [koːgʲəran] = quintuplet
còig-fillte = quintuple, fivefold
caogad [kɯːgəd] = fifty
Manx (Gaelg) queig [kwɛɡ] = five
queigagh, queigoo = fifth
queigad = fifty
queigin, queig-lhiatteean = pentagon
queigane = quintuplet
queig-filley = quintuple, five-fold
Proto-Brythonic *pɨmp [pɨmp] = five
*pɨmped [pɘmˈpɛːd] = fifth
Gaulish pimpe, pempe = five
pimpetos = fifth
Old Welsh pimp = five
petguaret = fifth
pimmunt = fifty
Middle Welsh (Kymraec) pimp, pym(p), pvmp, pum(p) = five
pimphet, pemhet, pimhed, pymhed, pymhet = fifth
pymthec = fifteen
pymwnt, pumhwnt, pemhwnt, pummwnt = fifty
pvmplyc, pymplyg, pumplyg = quintuple, fivefold
Welsh (Cymraeg) pump [pɨ̞mp/pɪmp] = five
pumed [pɛdˈwɛrɨ̞ð] (5ed) = fifth
pumplyg = quintuple, fivefold, folded five times
pumpunt = five pounds, five-pound note, fiver
pedwaraid = set of five, fivesome
pumseiniol = pentatonic (music)
Middle Cornish (Cernewec) pymp, pemp = five
pympes = fifth
pymthec, pemdhac = fifteen
Cornish (Kernewek) pymp = five
pympes, pempes = fifth
pymthek, pemdhek = fifteen
pympbys, pempbes = starfish (“five finger”)
Old Breton pemp = five
Middle Breton (Brezonec) pemp, puemb = five
pempet, peempet, pempvet = fifth
pempaat = to group into five
pempkement = quintuple
pempkementiñ = to quintuple
pempkogneg = pentagon
Breton (Brezhoneg) pemp [pɛmp/pɛ̃mp] = five
pemp(v)et = fifth
pemzek = fifteen
pempad = quintet
pempkorneg = pentagon

Etymology: from Proto-Indo-European *pénkʷe (five) [source].

English words from the same roots include five, fifth, fifty, fifty, quintet, and words beginning with penta-, such as pentathlon and pentameter [source].

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Fourfold

Words for four and related things in Celtic languages:

four

Proto-Celtic *kʷetwares = four
*kʷetwariyos = fourth
Gaulish petru, petuar = four
petuarios = fourth
Old Irish (Goídelc) cethair [ˈkʲeθirʲ] = four
cethramad [ˈkʲeθraṽað] = fourth
cethracha = forty
cethrar = four people
cethardúil = four elements
Middle Irish (Gaoidhealg) cethair = four
cethramad = fourth
cethrar = four people
cethracha = forty
cetharchair = four-sided, square, rectangular
cethairríad = four-wheeled chariot or carriage
cethardenus = space of four days
cethardóit = group of four
cetharaird = the four points of the compass, the four quarters, the world, universe
Irish (Gaeilge) ceathair [ˈcahəɾʲ/ˈcæɾʲ] = four, quadruped
ceithre [ˈcɛɾʲə/ˈçɛɾʲə] = four
ceathrar [ˈcahɾˠəɾˠ/cæːɾˠ] = four people
ceathracha = forty
ceathrú [cahˈɾˠuː] = quarter, thigh, quatrain
ceathrúnach = quartermaster
ceathairbhliantúil = quadrennial
ceathairchodach = fourfold, quadruple
ceathairchosach = fourfooted, quadruped
ceathairéad = quartet
ceathairfhillte = quarto, fourfold
Scottish Gaelic (Gàidhlig) ceithir [kʲehɪrʲ] = four
ceathramh [kʲɛrəv] (4mh) fourth (4th)
ceathrar [kʲɛrər] = four (people)
ceathrad [kʲɛrəd] = forty
cairteal [kar̪ˠʃdʲal] = quarter; quarters, lodgings
ceithir-chasach = quadruped, four-legged animal
ceithir-cheàrnach = quadrilateral
ceithir-fillte = quadruple, fourfold, four-ply
Manx (Gaelg) kiare [kʲeːə(r)] = four, foursome, quartet
kiarroo, (yn) chiarroo = (the) fourth
kerroo = fourth, quarter, quatrain
kiarad = forty
kiare-fillagh, kiare-filley = fourfold, quadruple
kiare-lhiatteeagh, kiare-lhiatteean = four-sided, quadrilateral
kiare-chassagh = four-footed, four-legged, quadruped
Proto-Brythonic *pedwar [pɛdˈwaːr] = four
*pėdwėrɨð [pe̝dwe̝ˈrˑɨːð] = fourth
Old Welsh petguar = four
petguaret = fourth
Middle Welsh (Kymraec) pedwar, peduar = four (m)
pedeyr, pedair, pedeir = four (f)
pedweryd = fourth (m)
pedwyred = fourth (m)
pedwar deg, pedeir deg = fourteen
pedwar/pedeir ar bymthec = nineteen
pedwar ugein(t) = eighty
Welsh (Cymraeg) pedwar [ˈpɛdwar] = four (m)
pedair [ˈpɛdai̯r/ˈpeːdai̯r] = four (f)
pedwerydd [pɛdˈwɛrɨ̞ð] (4ydd) = fourth (m)
pedwaredd [pɛdˈwarɛð] (4edd) = fourth (f)
pedwarplyg = quadruple
pedwaraf, pedwaru = to divide into four, quarter
pedwaraid = set of four, foursome
pedwar ar ddeg = fourteen
pedwar ar bymtheg = nineteen
pedwar deg = forty
pedwar ugain = eighty
Middle Cornish (Cernewec) peswar = four (m)
pedar = four (f)
peswere, pyswere = fourth
peswardhec, pazawardhak = fourteen
padzhar iganz = eighty
padzhar iganz ha deg = ninety
Cornish (Kernewek) peswar, pajar = four (m)
peder = four (f)
peswora, pajwora = fourth
peswartrosek = fourfooted
peswardhek = fourteen
peswar ugens = eighty
Old Breton petguar = four
petguare = fourth
Middle Breton (Brezonec) peuar, puar = four
peuare, pevare = fourth
peuarzec, pévarzecq, piarzeg = fourteen
peuaruguent, pêver huguent, pévar uguent = eighty
pevar-benveg = quartet
pevarc’hartier = to cut in quarters
pévar c’hemend = quadruple
pevar(-)c’hementi(ñ) = to quadruple
Breton (Brezhoneg) pevar = four (m)
peder = four (f)
pevare = fourth
pevarved = fourth (m)
pedervet = fourth (f)
pevarzek = fourteen
pevar-ugent = eighty
pevarad = quartet
pevarzuek = quadrilatéral

Etymology: from Proto-Indo-European *kʷetwóres (four) and *kʷetwr̥yós (fourth) [source].

English words from the same roots include four, quarter, quart, quartet, quaruple, and words beginning with tetra-, such as tetradecimal (a 14-base counting system) [source].

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic

Threesome

Words for three and related things in Celtic languages:

three

Proto-Celtic *trīs = three
*tritiyos = third (in a sequence)
*trisano- = third (fraction)
Celtiberian Tiriś = three
Gaulish treis = three (m)
tiđres = three (f)
Lusitanian *trīs = three
Old Irish (Goídelc) tri, trí [tʲrʲiː] = three
tress = third (in a sequence)
trían = third (fraction)
tríar = three (people)
tréide = three things
trédenus = three days
tréimse = three months
Middle Irish (Gaoidhealg) trí = three
tress = third (in a sequence), one of three
trímad = third (in a sequence)
trían = third (fraction)
tríar = three persons, trio, three things
tréimse = three months, a quarter (of a year)
Irish (Gaeilge) trí [tʲɾʲiː] = three
tríú [tʲɾʲiːuː] = third (in a sequence), third part
triúr [tʲɾʲuːɾˠ] = three (people)
triantán = triangle
triantánacht = trigonometry
triantánaigh = to triangulate
tríoiseach = three-dimensional
Scottish Gaelic (Gàidhlig) trì [triː] = three
treas [tres] (3ˢ) third (3ʳᵈ)
treasamh (3ᵐʰ) third (3ʳᵈ)
triùir [truːrʲ] = three (people)
trì-fillte = triple, threefold, three-ply
trian [triən] = third (part)
triantan [triəndan] = triangle
iantanachd [iantanachd] = trigonometry
Manx (Gaelg) tree [t̪riː] = three
troor = three (people), threesome, triad, Trinity, trio, trinity
treeoo, trass = third
trooane, troorane = triangle
Proto-Brythonic *tri [triː] = three (m)
*teir = three (f)
*trɨdɨð [trɨˈdɨːð] = third (m)
*trɨdeð = third (f)
Old Welsh *tri [triː] = three (m)
*teir = three (f)
tritid = third (in a sequence)
trean = third (fraction)
Middle Welsh (Kymraec) tri = three (m)
teir, tair = three (f)
trited, trydet, trydyd = third
teir coglaỼc, trichonglaỼc, trichongloc = triangular, three-cornered
trydeblyc, tridyblic = three times, threefold, triple
Welsh (Cymraeg) tri [triː] = three (m),
tair [tai̯r] = three (f)
triawd = trio, threesome, triology, triple
trichorn = three-horned, three-cornered, tricorn hat
tric(h)onglog = triangular, three-cornered
tri deg = thirty
tridyblyg = three times, threefold, triple, triplicate
trionglyn = triangle
trydydd (3ydd) = third (m)
trydedd (3edd) = third (f)
teirgwaith = three times, thrice, on three occasions
Middle Cornish (Cernewec) tri, trei = three (m)
teir, teyr = three (f)
triddydh = the space of three days
tridzha = third
trihans = three hundred
trindas, trinsys = Trinity
triugans = three score, sixty
trivorh = three-pronged
Cornish (Kernewek) tri, trei = three (m)
trei = three (f)
tredhek, terdhek = thirteen
tressa, tryja = third
triasen = triplet
trihorn = triangle
tryflek = threefold, triple
teyrgweyth = three times
Old Breton tri = three
Middle Breton (Brezonec) tri, try = three (m)
teir, teyr = three (m)
tri-c’hard = three quarters
tri-ugent = sixty
tri-chant = three hundred
triad = trio, group of three
tric’hogn, tricoign, tric’horn = triangle
Breton (Brezhoneg) tri = three (m)
teir [ˈte.iʁ] = three (f)
trived (m) teirved (f) = third
trizek = thirteen
tri-ugent = sixty
trifarzh = three quarters
tric’horn, tric’hogn = triangle

Etymology: from Proto-Indo-European *tréyes (three – m) and *tisres (three – f) [source].

English words from the same roots include tertiary, three, thrice, three, triad, tripod, triple and triplex [source].

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Gerlyvyr Cernewec, Dictionaire Favereau, TermOfis, Le dictionnaire diachronique du breton, Geriafurch, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic