Definition of: see-saw

(sē′sô′) noun
1. A sport in which persons sit or stand on opposite ends of a balanced plank and make it move up and down.
2. A plank or board balanced for this sport.
3. Any up–and–down or to–and–fro movement.
4. A crossruff.
—v.t. & v.i. To move or cause to move on or as if on a see–saw.
—adjective Moving to and fro; vacillating. [Reduplication of SAW¹ <See saw sack a downe, a sawyer's jingle]