The modern name of Exeter is a development of the Old EnglishEscanceaster, from the anglicised form of the river now known as the Exe and the Old English suffix-ceaster, used to mark important fortresses or fortified towns. (The Welsh name for the city, Caerwysg, similarly means "fortress on the Exe".) The name "Exe" is a separate development of the Brittonic name—meaning "water" or, more exactly, "full of fish" (cf. Welshpysg, pl. "fish")—that also appears in the EnglishAxe and Esk and the WelshUsk (Welsh: Wysg).