cavity

(noun) a sizeable hole (usually in the ground). Synonyms: pit. Example: "They dug a pit to bury the body."

(noun) space that is surrounded by something. Synonyms: enclosed space.

(noun) soft decayed area in a tooth; progressive decay can lead to the death of a tooth. Synonyms: caries, dental caries, tooth decay.

(noun) (anatomy) a natural hollow or sinus within the body. Synonyms: bodily cavity, cavum.