Abnormal uterine bleeding (AUB) in the reproductive years in non-pregnant women comprises a group of symptoms that include abnormal frequency and the irregular onset of flow as well as prolonged and heavy menstrual bleeding. It is a common, chronic, and debilitating condition affecting women worldwide with an adverse impact on their quality of life. Until the last decade, the "menstrual" terminology used to describe both normal and abnormal uterine bleeding and its underlying causes was inconsistent, creating considerable confusion. Using standardized terminology may potentially improve clinical management as well as help designing and interpreting basic, translational, epidemiological, and clinical research in women with menstrual problems. In this article, we explore the history and evolution of menstrual terminology and discuss the two International Federation of Gynecology and Obstetrics (FIGO) systems on i.e., (A) menstrual terminology and definitions (B) and the causes of AUB, achieved through international consensus of relevant stakeholders through a long multistage journey.