Operator

wiktionary

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Borrowed from Latin operatōr, from operor(“work, labour”). Equivalent to operate +‎ -or.

etymonline

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operator (n.)

1590s, "one who performs mechanical or surgical operations," agent noun from operate (v.) or from Late Latin operator "a worker." Meaning "one who carries on business shrewdly" is from 1828. Specific sense of "one who works a telephone switchboard" (1884) grew out of earlier meaning "one who works a telegraph" (1847).