Source : Webster's Revised Unabridged Dictionary (1913)

Third \Third\, n.
   1. The quotient of a unit divided by three; one of three
      equal parts into which anything is divided.

   2. The sixtieth part of a second of time.

   3. (Mus.) The third tone of the scale; the mediant.

   4. pl. (Law) The third part of the estate of a deceased
      husband, which, by some local laws, the widow is entitled
      to enjoy during her life.

   {Major third} (Mus.), an interval of two tones.

   {Minor third} (Mus.), an interval of a tone and a half.

Third \Third\ (th[~e]rd), a. [OE. thirde, AS. [thorn]ridda, fr.
   [thorn]r[=i], [thorn]re['o], three; akin to D. derde third,
   G. dritte, Icel. [thorn]ri[eth]i, Goth. [thorn]ridja, L.
   tertius, Gr. tri`tos, Skr. t[.r]t[=i]ya. See {Three}, and cf.
   {Riding} a jurisdiction, {Tierce}.]
   1. Next after the second; coming after two others; -- the
      ordinal of three; as, the third hour in the day. ``The
      third night.'' --Chaucer.

   2. Constituting or being one of three equal parts into which
      anything is divided; as, the third part of a day.

   {Third estate}.
      (a) In England, the commons, or the commonalty, who are
          represented in Parliament by the House of Commons.
      (b) In France, the tiers ['e]tat. See {Tiers ['e]tat}.

   {Third order} (R. C. Ch.), an order attached to a monastic
      order, and comprising men and women devoted to a rule of
      pious living, called the third rule, by a simple vow if
      they remain seculars, and by more solemn vows if they
      become regulars. See {Tertiary}, n., 1.

   {Third person} (Gram.), the person spoken of. See {Person},
      n., 7.

   {Third sound}. (Mus.) See {Third}, n., 3.

Source : WordNet®

third
     adj 1: coming next after the second and just before the fourth in
            position [syn: {3rd}, {tertiary}]
     2: being one of three equal parts; "a third share of the money"
        [syn: {third(a)}]

third
     adv : in the third place; "third we must consider unemployment"
           [syn: {thirdly}]

third
     n 1: one of three equal parts of a divisible whole; "it contains
          approximately a third of the minimum daily requirement"
          [syn: {one-third}, {tierce}]
     2: the fielding position of the player on a baseball team who
        is stationed near 3rd base; "he is playing third" [syn: {third
        base}]
     3: following the second position in an ordering or series; "a
        distant third"; "he answered the first question willingly,
        the second reluctantly, and the third with resentment"
     4: the musical interval between one note and another three
        notes away from it; "a simple harmony written in major
        thirds"
     5: the third from the lowest forward ratio gear in the gear box
        of a motor vehicle; "you shouldn't try to start in third
        gear" [syn: {third gear}]
     6: the base that must be touched third by a base runner in
        baseball; "he was cut down on a close play at third" [syn:
         {third base}]