"of or pertaining to the Welsh" and their kindred, the Cornish and Bretons, by 1833, from Welsh Cymru "Wales," Cymry "the Welsh," plural of Cymro, probably from ancient combrox "compatriot," from British Celtic *kom-brogos, from collective prefix *kom- (see com-) + *brogos "district," from PIE root *merg- "boundary, border." Compare Allobroges, name of a warlike people in Gallia Narbonensis, literally "those from another land." As from 1833 as a noun, "the language of the Cymry."