In mathematics, a well-defined action that, when applied to any permissible combination of known entities, produces a new entity, e.g. , the process of addition in arithmetic--in adding 5 and 3 to obtain 8, the numbers 5 and 3 are the operands, the number 8 is the result, and the plus sign is the operator indicating that the operation performed is addition. See unary operation, binary operation.
... (1304?-1377?), Moroccan Muslim, visited Mecca several times, travelled to Central Asia, East Africa, China, Tombouctou and other places
Nicholas Baudin[?] - 18th century ...