From WordNet (r) 3.0 (2006):
swelling
n 1: an abnormal protuberance or localized enlargement [syn:
swelling, puffiness, lump]
2: something that bulges out or is protuberant or projects from
its surroundings; "the gun in his pocket made an obvious
bulge"; "the hump of a camel"; "he stood on the rocky
prominence"; "the occipital protuberance was well developed";
"the bony excrescence between its horns" [syn: bulge,
bump, hump, swelling, gibbosity, gibbousness,
jut, prominence, protuberance, protrusion,
extrusion, excrescence]
3: the increase in volume of certain substances when they are
heated (often accompanied by release of water) [syn:
intumescence, intumescency, swelling]