WordNet (r) 3.0 (2006):

adding machine
    n 1: a calculator that performs simple arithmetic functions
         [syn: adding machine, totalizer, totaliser]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "adding machine":
   Comptometer, abacus, adding, analog computer, arithmograph,
   arithmometer, calculating machine, calculator, cash register,
   computation, counter, difference engine, digital computer,
   electronic computer, listing machine, pari-mutuel machine, quipu,
   rule, slide rule, sliding scale, suan pan, tabulator