1. [n]  a plaything that is ridden up and down by children at either end
2. [v]  move unsteadily, with a rocking motion
3. [v]  move up and down as if on a seesaw
4. [v]  ride on a plank

Seesaw
Description not available.

more details ...

1. \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}.
   

2. \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.
   

3. \See"saw`\, v. t.
   To cause to move backward and forward in seesaw fashion.
         He seesaws himself to and fro.           --Ld. Lytton.
   

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

An early system on the IBM 701.

[Listed in CACM 2(5):16 (May 1959)].