cavity in WordNet English dictionary

1. (anatomy) a natural hollow or sinus within the body
   cavity  bodily cavity  cavum 
   
2. soft decayed area in a tooth; progressive decay can lead to the death of a tooth
   cavity  caries  dental caries  tooth decay 
   
3. a sizeable hole (usually in the ground)
   "they dug a pit to bury the body"
   pit  cavity 
   
4. space that is surrounded by something
   cavity  enclosed space