Over the past 5 years there has been a major international discussion aimed at reaching agreement on the use of well-defined terminologies to describe the normal limits and range of abnormalities related to patterns of uterine bleeding. This article builds on concepts previously presented, which include the abandonment of long-used, ill-defined, and confusing English-language terms of Latin and Greek origin, such as menorrhagia and metrorrhagia. The term DYSFUNCTIONAL UTERINE BLEEDING should also be discarded. Alternative terms and concepts have been proposed and defined. The terminologies and definitions described here have been comprehensively reviewed and have received wide acceptance as a basis both for routine clinical practice and for comparative research studies. It is anticipated that these terminologies and definitions will be reviewed again on a regular basis through the International Federation of Gynecology and Obstetrics Menstrual Disorders Working Group.