exchequer (n.)

c. 1300, "a chessboard, checkerboard," from Anglo-French escheker "a chessboard," from Old French eschequier, from Medieval Latin scaccarium "chess board" (see check (n.1); also see checker (n.2)). The governmental sense of "department of the royal household concerned with the receipt, custody, and disbursement of revenue and with judicial determination of certain causes affecting crown revenues"  began under the Norman kings of England and refers to a cloth divided in squares that covered a table on which accounts of revenue were reckoned by using counters, and which reminded people of a chess board. Respelled with an -x- based on the mistaken belief that it originally was a Latin ex- word.