As a Noun: 1. The increase in size of something such that it becomes larger. English = expansion, enlargement. 2. The increase in size of something such that it becomes larger and rounder by being filled with liquid or air. English = swelling. 3. The increase in size of a body part such that it becomes larger and rounder than normal, usually as a result of an injury or an illness. English = swelling. As a Verb or Adjective: 1. To become larger. English = enlarge, expand. 2. To become larger and rounder by being filled with liquid or air. English = swell. 3. Of a body part, to become larger and rounder than normal, usually as a result of an injury or an illness. English = swell, swell up.