IPA: //ˈkæl.kjʊ.leɪ.tər//
KK: /ˈkæl.kjə.leɪ.tər/
A device or tool used to perform mathematical calculations, often electronically.
I used a calculator to help me with my math homework.
Calculator → It is formed from "calculus" (from Latin, meaning a small stone used for counting) and the suffix "-ator" (meaning one who or that which). The word "calculator" refers to one who counts or computes, originally using small stones for calculations.
Think of a 'small stone' used for counting — that's what 'calculator' means, as it refers to someone or something that counts or computes.