--noun (singular: hollow; plural: hollows)

1. a cavity or space in something.
  • "Hunger had caused the hollows in their cheeks."
2. holler: a small valley between mountains.
  • "He built himself a cabin in a hollow high up in the Appalachians."
3. hole: a depression hollowed out of solid matter.

--adj.

4. as if echoing in a hollow space.
  • "The hollow sound of footsteps in the empty ballroom."
5. devoid of significance or point.
  • "A hollow victory."

--adj.

6. not solid; having a space or gap or cavity.
  • "A hollow wall."

--verb usually used with object (verb: hollow; 3rd person present: hollows; past tense: hollowed; past participle: hollowed; gerund or present participle: hollowing)

7. to remove the interior of.
  • "Hollow out a tree trunk."
8. to remove the inner part or the core of.
Old English holh (n.) "hollow place, hole", from Proto Germanic *holhwo-, related to hol "hole" (see hole). The noun sense of "lowland, valley, basin" is 1553. The verb is from Middle English holowen. The figurative sense of "insincere" is attested from 1529. To carry it hollow "take it completely" is first recorded 1668, of unknown origin or connection.