This document defines several key terms used in mental health and psychiatric nursing. It provides definitions for terms like mental health, psychiatry, psychiatric nursing, and then proceeds to define over 50 additional terms used to describe various mental health conditions, behaviors, symptoms, and treatment approaches, including terms like abreaction, addiction, affect, agitation, amnesia, anxiety, apathy, delusion, dementia, hallucination, and mania. The document is intended to serve as a reference for terminology used in the fields of mental health and psychiatric nursing.