checker (Noun) — An attendant who checks coats or baggage.
checker (Noun) — One who checks the correctness of something.
checker (Noun) — (draughts) one of the flat round pieces used in playing the game of draughts.
checker (Verb) — Mark into squares or draw squares on; draw crossed lines on.
checker (Verb) — Variegate with different colours, shades, or patterns.