operator

1. operator
   Operator u kol centru mi je brzo pomogao. — The call center operator helped me quickly.
   Radi kao operator na građevinskoj mašini. — He works as a construction machine operator.
2. (in telecoms) carrier; network operator
   Koji mobilni operator imaš? — Which mobile carrier are you with?
3. (in math, programming) operator
   Ovaj operator poredi dve vrednosti. — This operator compares two values.

For people and mobile carriers the variant operater is also very common.