verb (v)

• move upwards in bubbles, as from the effect of heating; also used metaphorically(verb.motion)

  Synonym:
  bubble up
  

  source: wordnet30
• expand abnormally(verb.change)

  Synonym:
  swell, swell up, tumefy, tumesce
  

  source: wordnet30
• To enlarge or expand with heat; to swell; specifically, to swell up or bubble up under the action of heat, as before the blowpipe.(verb)

  source: webster1913