The buoyancy compensator vest, commonly known as a BC vest, is an essential piece of scuba diving equipment. It keeps divers afloat and provides stability underwater. However, there are several other terms used to refer to this piece of gear. One synonym is the buoyancy control device (BCD), which is more technical and refers to the vest's ability to adjust buoyancy. Another term is a diving vest or scuba vest, which is more general and can refer to any vest worn for diving purposes. Finally, the term lifejacket is also used to refer to a buoyancy vest, but this term can be misleading as it implies that the vest will keep the wearer afloat even if they are unconscious.