Celtic toponymy from Brythonic *"crüg" 'hill' (Irish "cruach") From tribal name "Dumnonii" or "Dumnones", from Celtic *"dumno-" 'deep', 'world' From Celtic *"dubr-" 'water', *"dubrās" 'waters' (Welsh "dwfr"; Breton "dour") First element is possibly "dun", ' hill fort' (Welsh ddin, 'fort'). First element from Celtic *"duro-" 'fort'; in "Dūrobrīvae", Celtic *"brīwa" 'bridge' Possibly derived from Brythonic *"iska", 'water, fish' and *"leith", 'damp, wet'. From Celtic *"iska" 'water' (Irish "uisce"); second element in "Isca Dumnoniorum" (Exeter) is a tribal name (see "Devon") From Brythonic *"lēd-" [from Celtic *"leito-"] + *"rïd-" [from Celtic *"(φ)ritu-"] = "Grey Ford" From Celtic *"lindo-" 'pool' + Latin "colonia" 'colony'
Celtic language decline in England a "vicus", and others end in elements denoting Roman features, such as "-caster", denoting "castra" ('forts'). There is a substantial body of names along the lines of "Walton"/"Walcot"/"Walsall"/"Walsden", many of which must include the Old English word "wealh" in the sense 'Celtic-speaker', and "Comberton", many of which must include Old English "Cumbre" 'Britons'. These are likely to have been names for enclaves of Brittonic-speakers─but again are not that numerous. In the last decade, however, scholars have stressed that Welsh and Cornish place-names from the Roman period seem no more likely to survive than Roman names in England: 'clearly name loss