n. [ From neuter of L. operandus, gerundive of operari. See Operate. ] (Math.) The symbol, quantity, or thing upon which a mathematical operation is performed; -- called also
a. [ L. operans, p. pr. of operari. See Operate. ] Operative. [ R. ] Shak. --
n. (Psychol.) A process for causing animals to behave in a specific manner by rewarding or punishing the animal each time it performs a certain act; after a time, the animal comes to associate the reward or punishment with the act, and will increase or decrease the frequency of performing that act. [ PJC ]