This chapter aims to help healthcare students and qualified health professionals to find and understand the meaning of key research terminology and, more importantly, develop their knowledge of some of the essential ideas and concepts they describe. It provides definition, application, and key revision points of the key research terminology starting with letter E, which is designed for revising and writing research-based assignments. The key research terminology includes ethics, ethics committee, ethnographic research, exclusion criteria, experimental design, and ex post facto studies.