The name "Chew" may have Celtic origins, cognate with the River Chwefru, cliwyf-ffrenwy, "the moving, gushing water"; ancient forms are Estoca (Chew Stoke), Chiu (Chew Magna), and Ciwetune (Chewton Mendip).[2] Its exact meaning admits of several possible explanations, including "winding water",[3] the ew being a variant of the French eau, "water". The word chewer is western dialect for "narrow passage" and chare is Old English for "turning."
Another theory is that the name derives from the Welsh cyw, "the young of an animal, or chicken", such that Afon Cyw would have meant "the river of the chickens".[4]
Other possible explanations are it comes from the Old English word cēo ("fish gill"), used in the transferred sense of a ravine, in a similar way to Old Norse gil, or possibly a derogatory nickname from Middle English chowe, "chough", Old English cēo, a bird closely related to the crow and the jackdaw, notorious for its chattering and thieving.[5] Still another suggestion is that the river is named after the Viking war god Tiw.[6]
The current course of the river was likely established after the last ice age, before which the river had probably followed the course of the Congresbury Yeo to the Bristol Channel. Ice blocking the Bristol Channel would have diverted the Chew such that it flowed north rather than west through Compton Martin to join the Avon.[7]
Fish ladders have been installed at three weirs in Keynsham and Chewton Keynsham to allow fish to travel upstream. Fishing rights for the Millground and Chewton sections of the river are owned by Keynsham Angling Club.[11] The Mill Ground stretch of the River Chew consists of the six left-bank fields (looking downstream) from Chewton Place at Chewton Keynsham to the Albert Mill, Keynsham. The water is home to numerous species of fish, including chub, roach, European perch, rudd, gudgeon, dace, grayling, trout, and eel.[citation needed]
"Notes on the names of parishes in the county of Somerset", Notes and Queries 15 September 1883:204, drawing upon Eyton, Domesday Studies and Collinson, Somerset.
Ekwall, Eilert (1928). English River-Names. Oxford University Press. ISBN 0-19-869119-X. Robinson, Stephen (1992). Somerset Place Names. Wimbourne: The Dovecote Press Ltd. ISBN 1-874336-03-2. Haslett, Simon K. (2010). Somerset Landscapes: Geology and landforms. Usk: Blackbarn Books. pp. 116–118. ISBN 9781456416317. Havinden, Michael. The Somerset Landscape. The making of the English landscape. London: Hodder and Stoughton. p. 71. ISBN 0-340-20116-9.