Hand washing is the act of cleaning the hands with the use of clean, running water (warm or cold) together with soap, for the purpose of removing soil, dirt, and/or microorganisms.
An operational definition is a detailed specification of how one would go about measuring a given variable; item or phenomenon. It can range from very simple and straightforward to quite complex, depending on the nature of the variable and the needs of the researcher.
The best way to illustrate the process of developing operational definitions for variables is to identify several theoretical constructs and develop multiple operational definitions of each.
Here are some examples of operational definitions shared by Ablongman.com.