OB

OB is an initialism used in several fields to denote different concepts, most commonly in medicine and in organizational studies. In medicine, OB stands for obstetrics, the branch of medicine that focuses on pregnancy, childbirth, and the postpartum period. The term is frequently abbreviated as OB in clinical notes and is part of the umbrella term OB-GYN, which combines obstetrics and gynecology. An obstetrician is a physician who specializes in this area and manages prenatal care, labor and delivery, and often high-risk pregnancies.

In the social and behavioral sciences, OB stands for organizational behavior. This interdisciplinary field studies how people behave in organizational settings, including topics such as motivation, leadership, communication, decision making, teamwork, and organizational culture. Findings in organizational behavior inform management practices, human resources, and organizational development.

Other uses of OB exist but are context-dependent and far less universal. In finance or trading contexts, OB can appear as shorthand for order book. In alumni or social contexts, OB may refer to old-boy networks or related associations. Because meanings are highly context-specific, clarifying the intended domain is important when encountering the abbreviation OB.