Real Dictionary

operationalism in American English
the doctrine that no concept or term used in a purportedly factual statement has valid meaning unless it can be defined in terms of repeatable, empirical operations, experimental procedures, etc.
noun: the doctrine that the meaning of a scientific term, concept, or proposition consists of the operation or operations performed in defining or demonstrating it

operationalism in British English
noun: the theory that scientific terms are defined by the experimental operations which determine their applicability