bulge

A bulge is a rounded projection or protrusion that extends outward from a surface. The term is used in many contexts to describe visible swelling, expansion, or collection of material. In everyday use, bulges may refer to body contours, structural deformities, or features on objects and landscapes.

In human anatomy and physiology, bulges can arise from muscle development, swelling, or natural anatomical landmarks that jut outward. For example, flexed muscles may create a prominent bulge, while injury or disease may produce an abnormal lump that the body perceives as a bulge. Bulges can also occur in clothing, resulting from the way fabric or padding shapes the silhouette.

In astronomy, a galactic bulge is the central, densely populated region of a spiral or lenticular galaxy. The bulge generally contains older stars and shows different stellar motions and chemical composition than the surrounding disk. Bulges are thought to form through early rapid collapse and later accretion or by secular evolution within galaxies.

In history and military usage, the Battle of the Bulge refers to the German offensive through the Ardennes during World War II, from December 1944 to January 1945. The operation aimed to split Allied forces and seize critical supply routes and territory, representing a major and contested turning point in the war.

As a verb, bulge means to protrude or swell outward. Objects may bulge under pressure, and the term appears in technical contexts such as pressure bulges in containers, pipes, and other thin-walled structures.