Someone who has an operation.

(calculus) A differential operator that preserves mathematical smoothness.

plural of floating point operation

plural of operating theatre

plural of operating room

A covert operation typically involving activities that are highly clandestine and outside of standard military protocol.

plural of black operation

Alternative spelling of uncooperative

(mathematics, functional analysis) An operator L such that for functions f and g and scalar λ, L (f + g) = L f + L g and L λf = λ L f.

Attending opera performances.