This document discusses different definitions of abnormality in psychology. It notes that defining something as abnormal implies it is undesirable and in need of change, so the term must be used carefully. Three definitions are presented: statistical infrequency, where a trait is abnormal if it is rare; deviation from social norms, where behavior is abnormal if it violates unwritten social rules; and lack of objectivity, where an abnormal definition should not depend on opinions and should produce consistent results. Context is important for the social norms definition, considering the degree and importance of any norm violations.