To bulge is to stick out, making a bump called a bulge. A leak in the roof might make your ceiling bulge, and a giant feast could make a bulge over your waistband.
The word bulge comes from the Old French word bouge for "wallet.” A full wallet makes a bulge in a guy’s back pocket. Bodybuilders' muscles bulge out of their bodies. A pimple is a tiny bulge on your skin. For the record, Battle of the Bulge isn’t a diet plan. It was a battle in World War II. Americans called it the Battle of the Bulge because of the way the Allied front line bulged inward.