Definition:Operator

An operator is a symbol which can be interpreted as a process which, from a number of objects, creates a new object.

The objects it operates on are called operands.

An example of an operator, from conventional arithmetic, is "$$+$$", as in, for example, "$$2 + 3 = 5$$". The operands (in this particular instance) are $$2$$ and $$3$$.

The number of operands an operator takes is called its arity or its valency.