Source : Webster's Revised Unabridged Dictionary (1913)

Alternate \Al*ter"nate\ (?; 277), a. [L. alternatus, p. p. of
   alternate, fr. alternus. See {Altern}, {Alter}.]
   1. Being or succeeding by turns; one following the other in
      succession of time or place; by turns first one and then
      the other; hence, reciprocal.

            And bid alternate passions fall and rise. --Pope.

   2. Designating the members in a series, which regularly
      intervene between the members of another series, as the
      odd or even numbers of the numerals; every other; every
      second; as, the alternate members 1, 3, 5, 7, etc.; read
      every alternate line.

   3. (Bot.) Distributed, as leaves, singly at different heights
      of the stem, and at equal intervals as respects angular
      divergence. --Gray.

   {Alternate alligation}. See {Alligation}.

   {Alternate angles} (Geom.), the internal and angles made by
      two lines with a third, on opposite sides of it. It the
      parallels AB, CD, are cut by the line EF, the angles AGH,
      GHD, as also the angles BGH and GHC, are called alternate
      angles.

   {Alternate generation}. (Biol.) See under {Generation}.

Alternate \Al*ter"nate\ (?; 277), n.
   1. That which alternates with something else; vicissitude.
      [R.]

            Grateful alternates of substantial.   --Prior.

   2. A substitute; one designated to take the place of another,
      if necessary, in performing some duty.

   3. (Math.) A proportion derived from another proportion by
      interchanging the means.

Alternate \Al"ter*nate\ (?; 277), v. t. [imp. & p. p.
   {Alternated}; p. pr. & vb. n. {Alternating}.] [L. alternatus,
   p. p. of alternare. See {Altern}.]
   To perform by turns, or in succession; to cause to succeed by
   turns; to interchange regularly.

         The most high God, in all things appertaining unto this
         life, for sundry wise ends alternates the disposition
         of good and evil.                        --Grew.

Alternate \Al"ter*nate\, v. i.
   1. To happen, succeed, or act by turns; to follow
      reciprocally in place or time; -- followed by with; as,
      the flood and ebb tides alternate with each other.

            Rage, shame, and grief alternate in his breast. --J.
                                                  Philips.

            Different species alternating with each other.
                                                  --Kirwan.

   2. To vary by turns; as, the land alternates between rocky
      hills and sandy plains.

Source : WordNet®

alternate
     adj 1: every second one of a series; "the cleaning lady comes on
            alternate Wednesdays"; "jam every other day"- the
            White Queen [syn: {alternate(a)}]
     2: allowing a choice; "an alternative plan" [syn: {alternative}]
     3: occurring by turns; first one and then the other;
        "alternating feelings of love and hate" [syn: {alternate(a)},
         {alternating(a)}]
     4: of leaves and branches etc; first on one side and then on
        the other in two ranks along an axis; not paired; "stems
        with alternate leaves" [ant: {opposite}]

alternate
     n : someone who takes the place of another person [syn: {surrogate},
          {replacement}]
     v 1: go back and forth; swing back and forth between two states
          or conditions [syn: {jump}]
     2: exchange people temporarily to fulfill certain jobs and
        functions
     3: be an understudy or alternate for a role [syn: {understudy}]
     4: reverse (a direction, attitude, or course of action) [syn: {interchange},
         {tack}, {switch}, {flip}, {flip-flop}]
     5: do something in turns; "We take turns on the night shift"
        [syn: {take turns}]