chamfered (adj.)

c. 1600, "small groove cut in wood or stone," from French chanfraindre (15c., Modern French chanfreiner), past participle of chanfraint, a word of uncertain origin. The second element seems to be from Latin frangere "to break" (from PIE root *bhreg- "to break"); perhaps the whole word is cantum frangere "to break the edge."

The meaning "sloping surface in place of a square edge or corner" is attested from c. 1840, but the connection to the other sense is uncertain. As a verb from 1560s, "cut a furrow in;" from 1680s as "cut or grind into a symmetrical sloping edge." Related: Chamfering.