Words for dwelling / settlement / town in Celtic languages.
|Proto-Celtic||*trebā = dwelling|
|Gaulish||Atrebates = name of a tribe|
|Old Irish (Goídelc)||treb = house, farm; household; tribe|
|Irish (Gaeilge)||treibh [ˈtʲɾʲɛv] = house, homestead, farmstead; household, family; tribe, race|
|Scottish Gaelic (Gàidhlig)||treabh [tro] = farming village
treubh [treːv] = tribe
|Proto-Brythonic||*treβ [ˈtrɛːβ] = town, settlement|
|Middle Welsh (Kymraec)||tref [ˈtrɛːβ] = town, settlement|
|Welsh (Cymraeg)||tre(f) [treːv] = town; town centre; dwelling(-place), habitation, residence, home; house (and surrounding land), homestead, farm, estate, cluster of houses; township; tribe|
|Cornish (Kernewek)||trev [trɛ:v /tre:v] = farmsteads (singular: treven)|
|Old Breton||treff = town, settlement|
|Breton (Brezhoneg)||trev = town|
From the Proto-Indo-European *treb- (dwelling, settlement) [source].
This is also the root of the archaic English word thorp(e) (a group of houses standing together in the country; a hamlet; a village), which appears in place names such as Milnthorpe and Scunthorpe.
Related words in other languages include German Dorf (hamlet, village, town), Danish torp (village), Swedish torp (farm, cottage, croft), Icelandic þorp (village, farm), and Albanian trevë (country, region, village) [source].
Words marked with a * are reconstructions.