operandum

Operandum is a Latin noun used in scholastic and early scientific Latin to denote the object on which an operation is performed, or more generally, an instrument or tool of an operation. In mathematical and logical contexts, operandum corresponds to the English term operand—the value, variable, or object supplied to an operator.

Origin and form: The word derives from the Latin verb operare "to work" and the morphology of the neuter noun operandum, literally “that which is to be operated on.” In use, it serves to distinguish the entity acted upon from the operator itself.

Usage: In medieval and early modern texts, operandum is employed to differentiate the thing subjected to an operation from the acting symbol or function. It appears in glossaries and commentaries on arithmetic, algebra, and logic, where authors discuss the relationship between an operator (such as plus, times, or a function) and the operand it operates on.

Modern relevance: Today operandum is primarily of historical interest, appearing in discussions of Latin translations of mathematical and logical works. In contemporary Latin scholarship, the concept is often rendered through direct adoption of the English term operand or by descriptive phrases such as “res operanda” or “instrumentum operationis,” depending on context.

See also: operand, operator.