Source : Webster's Revised Unabridged Dictionary (1913)

Seesaw \See"saw`\, n. [Probably a reduplication of saw, to
   express the alternate motion to and fro, as in the act of
   sawing.]
   1. A play among children in which they are seated upon the
      opposite ends of a plank which is balanced in the middle,
      and move alternately up and down.

   2. A plank or board adjusted for this play.

   3. A vibratory or reciprocating motion.

            He has been arguing in a circle; there is thus a
            seesaw between the hypothesis and fact. --Sir W.
                                                  Hamilton.

   4. (Whist.) Same as {Crossruff}.

Seesaw \See"saw`\, v. i. [imp. & p. p. {Seesawad}; p. pr. & vb.
   n. {Seesawing}.]
   To move with a reciprocating motion; to move backward and
   forward, or upward and downward.

Seesaw \See"saw`\, v. t.
   To cause to move backward and forward in seesaw fashion.

         He seesaws himself to and fro.           --Ld. Lytton.

Seesaw \See"saw`\, a.
   Moving up and down, or to and fro; having a reciprocating
   motion.

Source : WordNet®

seesaw
     n : a plaything consisting of a board balanced on a fulcrum; the
         board is ridden up and down by children at either end
         [syn: {teeter-totter}, {teeterboard}, {tilting board}, {dandle
         board}]
     v 1: ride on a plank
     2: move up and down as if on a seesaw
     3: move unsteadily, with a rocking motion [syn: {teeter}, {totter}]

Source : Free On-Line Dictionary of Computing

SEESAW
     
         An early system on the {IBM 701}.
     
        [Listed in CACM 2(5):16 (May 1959)].
     
        (1994-12-15)