Definition of arithmetician in US English:

arithmetician

noun

  • An expert in the use of numbers in counting and calculation.

    ‘I wanted a good arithmetician to keep an exact account of our outgoings’

Pronunciation

arithmetician

/əˌrɪθməˈtɪʃ(ə)n//əˌriTHməˈtiSH(ə)n/