(mathematics, computing) A quantity to which an operator is applied (in 3-x, the operands of the subtraction operator are 3 and x).

plural of operand

A lever, key or device installed in a operant chamber, upon which the "subject" exerts its responses. Sometimes referred to as a manipulandum. In the prototypical operant conditioning experiment, a rat (the subject) presses upon a lever (the operandum) which triggers the delivery of food (the reward or reinforcer).

(colloquial) A person or thing's normal mode of operation.

plural of modus operandi

Misconstruction of modus operandi

Misconstruction of modus operandi

plural of operandum

plural of modus operandi