Abacus

Chamber's Twientieth Century Dictionary · 1908 · p. 4

ab′a-kus, n. a counting-frame or table: ( arch it. ) a level tablet on the capital of a column, supporting the entablature:— pl. Ab′acī .— ns. Abacis′cus , Abac′ulus , dims. of Abacus ; Ab′acist , one who counts with the abacus. [L.—Gr. abax , abakos , a board for reckoning on.]