say it: SEE-saw
seesaw is a verb and noun meaning "ride on a plank". It carries 4 recorded senses.
ride on a plank
move up and down as if on a seesaw
move unsteadily, with a rocking motion
a plaything consisting of a board balanced on a fulcrum; the board is ridden up and down by children at either end
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for seesaw come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.