A "criterion" is a standard or principle used to judge or evaluate something. It helps in making decisions by providing a clear basis for comparison. For example, when selecting a candidate for a job, employers may use criteria such as experience, skills, and education to determine who is the best fit. In various fields, criteria can vary widely. In science, researchers might use specific criteria to assess the validity of an experiment, while in art, critics may evaluate a painting based on criteria like technique, originality, and emotional impact.