Late Middle English; earliest use found in John Trevisa (c1342–?1402), translator. From post-classical Latin abacista arithmetician from classical Latin abacus + -ista.
Definition of abacist in US English:
abacist
nounˈabəsɪst
A person who makes calculations using an abacus.
Origin
Late Middle English; earliest use found in John Trevisa (c1342–?1402), translator. From post-classical Latin abacista arithmetician from classical Latin abacus + -ista.