/op"euh ray'teuhr/ , n.
1. a person who operates a machine, apparatus, or the like: a telegraph operator.
2. a person who operates a telephone switchboard, esp. for a telephone company.
3. a person who manages a working or industrial establishment, enterprise, or system: the operators of a mine.
4. a person who trades in securities, esp. speculatively or on a large scale.
5. a person who performs a surgical operation; a surgeon.
6. Math.
a. a symbol for expressing a mathematical operation.
b. a function, esp. one transforming a function, set, etc., into another: a differential operator.
7. Informal.
a. a person who accomplishes his or her purposes by devious means; faker; fraud.
b. a person who is adroit at overcoming, avoiding, or evading difficulties, regulations, or restrictions.
c. a person who is extremely successful with or smoothly persuasive to members of the opposite sex.
8. Genetics. a segment of DNA that interacts with a regulatory molecule, preventing transcription of the adjacent region.
[ 1590-1600; opera ( ri ) to work, effect (see OPERATE) + L -tor -TOR ]