late 14c., "mathematician, one who calculates," from Latin calculator, from calculatus, past participle of calculare "to reckon, compute," from calculus "reckoning, account" (see calculus). Of mechanical adding machine contraptions, from 1784. Of electronic ones, from 1946.

Electronic calculator uses 18,000 tubes to solve complex problems [Scientific American headline, June 1946]

calcium

calculate

calculated

calculating

calculation

calculator

calculous

calculus

Calcutta

caldera

caldron