Words for eight and related things in Celtic languages:
| 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