In January 2013, an international group of simulation experts gathered in Orlando, Florida, U.S.A. to form a working team whose mission was to create a dictionary of terms used in health care simulation. This group recognized a need to compile terms that had been completed by other groups in health care simulation and to add more terms. The document you see represents the work of many individuals and their societies to compile and refine the dictionary. The goal of this project is to enhance communication and clarity for health care simulationists in teaching, education, assessment, research, and systems integration activities. The Agency for Health care Research and Quality (AHRQ) has partnered with the Society for Simulation in Healthcare and its many affiliates to produce the first comprehensive Healthcare Simulation Dictionary and disseminate it widely as part of AHRQ’s mission to improve patient safety, which includes simulation research.