Definition of "cavern"

cavern

/ˈkav.ən/

noun
plural caverns
1. A large cave.
2. An underground chamber.
  Quotations
  In Xanadu did Kubla Khan / A stately pleasure-dome decree: / Where Alph, the sacred river, ran / Through caverns measureless to man / Down to a sunless sea.
  1797, S[amuel] T[aylor] Coleridge, “Kubla Khan: Or A Vision in a Dream”, in Christabel: Kubla Khan, a Vision: The Pains of Sleep, London: […] John Murray, […], by William Bulmer and Co. […], published 1816, page 55
3. A large, dark place or space.
verb
third-person singular simple present caverns, present participle caverning, simple past and past participle caverned
1. (transitive) To form a cavern or deep depression in.
2. (transitive) To put into a cavern.