Merriam-Webster's Collegiate® Dictionary, 11th Edition
CHECKER
I. noun see: check
Date: 14th century
chessboard , a square or spot resembling the markings of a checkerboard, a piece in checkers,
II. transitive verb (checkered; checkering)
Date: 15th century
1. to variegate with different colors or shades, to vary with contrasting elements or situations, to mark into squares,
III. noun
Date: 1535
one that checks , an employee who checks out purchases in a self-service store