mate: [14] Mate ‘friend’ and mate the chess term are two distinct words. The former was borrowed from Middle Low German mate or gemate ‘companion’ (source also of Dutch maat), which goes back to a prehistoric West Germanic *gamaton. This was formed from the collective prefix *ga- and *mat- ‘measure’, which was also the source of English meat; so etymologically mate (like companion) is ‘someone you eat with or share your food with’.
The chess term mate comes from Old French mat ‘dead’. This was short for eschec mat (source of English checkmate), which comes from Persian shāh māt ‘the king is dead’. Persian māt ‘dead’ also contributed the verb matar ‘kill’ to Spanish, from which was derived matador [17], literally ‘killer’. => meat; mat, matador, matte
