Operational definition refers to the concrete and specific definition of something in terms of the operations by which observations are to be categorized; a definition of a concept in terms of the operations that must be performed to demonstrate the concept. Operational definition is the definition of a concept by specifying the operations required to manipulate or measure the concept. It is defining a scientific concept by stating the specific actions or procedures used to measure it. For example, "hunger" might be defined as "the number of hours of food deprivation. "
Lexicon of Psychology - Terms, Treatments, Biographies,