Swell means to grow larger or puff up, usually gradually. When you twist your ankle, it might swell up as fluid collects around the injury. Bread dough swells as the yeast produces tiny gas bubbles. A river can sell after heavy rains, rising higher and flowing faster than usual.

The word also describes waves in the ocean. Ocean swells are smooth, rolling waves that travel across deep water, created by distant storms or winds. Sailors pay close attention to swells because they affect how a boat moves. Unlike choppy waves near shore, swells are more regular and predictable.

As an old-fashioned slang term, swell means excellent or wonderful. In the early 1900s, someone might say “That's swell!” the way you might say “That's awesome!” today. You still see this usage in old movies and books, though it sounds charmingly outdated now.

When someone's heart swells with pride, it means they feel an overwhelming sense of happiness and pride, as if their chest is filling up with the emotion. The phrase captures that physical feeling of intense positive emotion.