What is the Latin word for arithmetic?

The usual Latin words for “arithmetic” are arithmētica, arithmēticus, sum. The right choice depends on the sense; see the distinctions below.

English → Latin

“arithmetic” in Latin

arithmēticaarithmetic arithmēticusarithmetical sumto be, exist; there be; to go

The English word arithmetic itself goes back to Latin arithmētica.

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

arithmetic

arithmetica, orum (Cic..): arithmetice, es, or arithmetica, ae: notitia numerorum (the knowledge of numbers, geturaliy, Quint., 1, 10, 35). To teach arthmetic, arithmetica profiteri. A teacher of arithmetic, arithmeticorum magister.

An arithmetic book, liber arithmeticus.

Quick answer

What is the Latin word for arithmetic?: The usual Latin words for “arithmetic” are arithmētica, arithmēticus, sum. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.