also seesaw, 1630s, in see-saw-sacke a downe (like a Sawyer), words in a rhythmic jingle used by children and repetitive-motion workers, probably imitative of the rhythmic back-and-forth motion of sawyers working a two-man pit saw (see saw (n.1). Ha ha.).
In reference to a children's sport of going alternately up and down on a plank balanced on some support, it is recorded from 1704; the figurative sense of this is from 1714. Applied from 1824 to the plank arranged and adjusted for the game. Also compare teeter-totter under teeter (v.).