MATE (5)

Mate, n. [[Perhaps for older make a companion; cf. also OD. maet companion, mate, D. maat. Cf. Make a companion, Match a mate.]] 1. 1. One who customarily associates with another; a companion; an associate; any object which is associated or combined with a similar object.
2. 2. Hence, specifically, a husband or wife; and among the lower animals, one of a pair associated for propagation and the care of their young.
3. 3. A suitable companion; a match; an equal.
Ye knew me once no mate For you; there sitting where you durst not soar. Milton. 4. 4. (Naut.) An officer in a merchant vessel ranking next below the captain. If there are more than one bearing the title, they are called, respectively, first mate, second mate, third mate, etc. In the navy, a subordinate officer or assistant; as, master's mate; surgeon's mate.