-ˌlād.ə(r), -ātə- noun
( -s )
Etymology: Middle English, from Latin, from calculatus + -or
1. : one that calculates: as
a. : calculating machine
b. : a person who operates a calculating machine especially in checking figures in financial or statistical papers
c. : a computing clerk and supervisor of a mutuel department who calculates the amounts due to patrons holding parimutuel tickets on the leading horses in each race
2. : a set or book of tables for facilitating computations : ready reckoner