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'
Isca Dumnoniorum Fosse Way, and on the 7th-century Ravenna Cosmography, where it appears as the apparently confused entry of . The fortress was given up around 75 and shortly afterwards its grounds were converted to civilian purposes. The military baths were too large for the local population and were largely demolished, although parts were incorporated into the forum and basilica built on the site. A smaller bathhouse was then built to the southeast. In the late 2nd century, the ditch and rampart defences around the fortress were replaced by a bank and wall enclosing a much larger area, some 92 acres (37