The Collaborative International Dictionary of English v.0.48:

Mate \Mate\ (m[=a]t), n. [F. mat, abbrev. fr. ['e]chec et mat.
   See Checkmate.] (Chess)
   Same as Checkmate.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mate \Mate\, a.
   See 2d Mat. [Obs.] --Chaucer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mate \Mate\, v. t. [F. mater to fatigue, enfeeble, humiliate,
   checkmate. See Mate checkmate.]
   [1913 Webster]
   1. To confuse; to confound. [Obs.] --Shak.
      [1913 Webster]

   2. To checkmate.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mate \Mate\, n. [Perhaps for older make a companion; cf. also
   OD. maet companion, mate, D. maat. Cf. Make a companion,
   Match a mate.]
   1. One who customarily associates with another; a companion;
      an associate; any object which is associated or combined
      with a similar object.
      [1913 Webster]

   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.
      [1913 Webster]

   3. A suitable companion; a match; an equal.
      [1913 Webster]

            Ye knew me once no mate
            For you; there sitting where you durst not soar.
                                                  --Milton.
      [1913 Webster]

   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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mate \Ma"te\ (m[aum]"t[asl]), n. [Sp.]
   The Paraguay tea, being the dried leaf of the Brazilian holly
   (Ilex Paraguensis). The infusion has a pleasant odor, with
   an agreeable bitter taste, and is much used for tea in South
   America.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mate \Mate\, v. i.
   To be or become a mate or mates, especially in sexual
   companionship; as, some birds mate for life; this bird will
   not mate with that one.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mate \Mate\, v. t. [imp. & p. p. Mated; p. pr. & vb. n.
   Mating.]
   1. To match; to marry.
      [1913 Webster]

            If she be mated with an equal husband. --Shak.
      [1913 Webster]

   2. To match one's self against; to oppose as equal; to
      compete with.
      [1913 Webster]

            There is no passion in the mind of man so weak but
            it mates and masters the fear of death. --Bacon.
      [1913 Webster]

            I, . . . in the way of loyalty and truth, . . .
            Dare mate a sounder man than Surrey can be. --Shak.
      [1913 Webster]

   3. To breed; to bring (animals) together for the purpose of
      breeding; as, she mated a doberman with a German shepherd.
      [PJC]

   4. To join together; to fit together; to connect; to link;
      as, he mated a saw blade to a broom handle to cut
      inaccessible branches.
      [PJC]

WordNet (r) 3.0 (2006):

mate
    n 1: the officer below the master on a commercial ship [syn:
         mate, first mate]
    2: a fellow member of a team; "it was his first start against
       his former teammates" [syn: teammate, mate]
    3: the partner of an animal (especially a sexual partner); "he
       loved the mare and all her mates"; "camels hate leaving their
       mates"
    4: a person's partner in marriage [syn: spouse, partner,
       married person, mate, better half]
    5: an exact duplicate; "when a match is found an entry is made
       in the notebook" [syn: match, mate]
    6: one of a pair; "he lost the mate to his shoe"; "one eye was
       blue but its fellow was brown" [syn: mate, fellow]
    7: South American holly; leaves used in making a drink like tea
       [syn: mate, Paraguay tea, Ilex paraguariensis]
    8: informal term for a friend of the same sex
    9: South American tea-like drink made from leaves of a South
       American holly called mate
    10: a chess move constituting an inescapable and indefensible
        attack on the opponent's king [syn: checkmate, mate]
    v 1: engage in sexual intercourse; "Birds mate in the Spring"
         [syn: copulate, mate, pair, couple]
    2: bring two objects, ideas, or people together; "This fact is
       coupled to the other one"; "Matchmaker, can you match my
       daughter with a nice young man?"; "The student was paired
       with a partner for collaboration on the project" [syn:
       match, mate, couple, pair, twin]
    3: place an opponent's king under an attack from which it cannot
       escape and thus ending the game; "Kasparov checkmated his
       opponent after only a few moves" [syn: checkmate, mate]

Moby Thesaurus II by Grady Ward, 1.0:

244 Moby Thesaurus words for "mate":
   OD, accompanier, accompanist, accompanyist, ace, acquaintance,
   ally, alter ego, amigo, analogon, analogue, associate, attendant,
   ball, be intimate, be made one, be spliced, become one, bedfellow,
   bedmate, better half, birthmate, boatswain, bosom buddy, bracket,
   breed, bride, brother, buddy, bunkie, bunkmate, butty, camarade,
   captain, chamberfellow, chap, chief engineer, chief mate, china,
   chum, classmate, close copy, close match, clubmate, co-worker,
   coequal, cognate, cohabit, cohort, colleague, comate,
   come together, commander, commit adultery, companion,
   companion piece, company, compeer, complement, comrade,
   concomitant, confidant, confrere, congenator, congener, conjugate,
   consociate, consort, contract matrimony, coordinate, copartner,
   copemate, copesmate, copulate, copy, correlate, correlative,
   correspondent, couchmate, counterpart, couple, couple up, cover,
   cradlemate, crony, crossbreed, cupmate, dead ringer, deck officer,
   diddle, ditto, double, double-harness, double-team, duplicate,
   effigy, equal, equipollent, equivalent, espouse, exact likeness,
   familiar, fellow, fellow student, fit together, fornicate, friend,
   frig, general partner, generate, get hitched, girl friend, gossip,
   have sex, have sexual relations, helpmate, helpmeet, hitch, hubby,
   husband, icon, idol, image, intermarry, interwed, intimate,
   jailmate, join, kindred spirit, lay, lie with, like, likeness,
   link up, living image, living picture, make it with, make love,
   make out, marry, master, match, messmate, miniature, mirroring,
   miscegenate, model, mount, naval officer, navigating officer,
   navigator, near duplicate, obverse, old crony, opposite number,
   pair, pair off, pal, parallel, pard, pardner, partner, patron,
   peer, pendant, pewmate, photograph, picture, pipes, playfellow,
   playmate, portrait, procreate, quartermaster, reciprocal,
   reflection, remarry, resemblance, rewed, rival, roommate, rubbing,
   sailing master, schoolfellow, schoolmate, screw, second mate,
   second self, secret partner, semblance, serve, service, shadow,
   shelfmate, shipmaster, shipmate, shopmate, side partner, sidekick,
   sidekicker, silent partner, similitude, simulacrum, sister,
   skipper, sleep with, sleeping partner, soul mate, span,
   special partner, spit and image, spitting image, splice, spouse,
   such, suchlike, synchronize, tablemate, take to wife, tally, team,
   team up, teammate, tentmate, the Old Man, the like of,
   the likes of, tie, trace, tracing, twin, unite, very image,
   very picture, watch officer, watchmate, waymate, wed, wife, wive,
   workfellow, yoke, yokefellow, yokemate



Bouvier's Law Dictionary, Revised 6th Ed (1856):

MATE. The second officer on board of a merchant ship or vessel.
     2. He has the right to sue in the admiralty as a common mariner for
wages. 1. Pet. Adm. Dee. 246.
     3. When, on the death of the master, the mate assumes the command, he
succeeds to the rights and duties of the principal officer. 1 Sumn. 157; 3
Mason, 161; 4 Mason, 196; See 7 Conn. 239; 4 Mason, 641 4 Wash. C. C. 838.