The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

   2. A plank or board adjusted for this play.
      [1913 Webster]

   3. A vibratory or reciprocating motion.
      [1913 Webster]

            He has been arguing in a circle; there is thus a
            seesaw between the hypothesis and fact. --Sir W.
                                                  Hamilton.
      [1913 Webster]

   4. (Whist.) Same as Crossruff.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Seesaw \See"saw`\, v. t.
   To cause to move backward and forward in seesaw fashion.
   [1913 Webster]

         He seesaws himself to and fro.           --Ld. Lytton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Seesaw \See"saw`\, a.
   Moving up and down, or to and fro; having a reciprocating
   motion.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Crossruff \Cross"ruff`\ (-r?f`), n. (Whist)
   The play in bridge or whist where partners trump each a
   different suit, and lead to each other for that purpose; --
   called also seesaw.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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

The Free On-line Dictionary of Computing (19 January 2023):

SEESAW

    An early system on the IBM 701.

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

   (1994-12-15)