Synonyms for Cavern:

n.

crevice, chasm, fissure, ditch, crevasse, rift, pothole, gully. convex, cave, grotto. cave (noun)
grotto, hollow.
cavern (noun)
cavern out.
hollow in land formation (noun)
grotto, cave, pothole.

v.

contact (verb)
cavern out.

Other synonyms:

crevasse. chasm, gully, pothole, grotto. cave, ditch. Other relevant words:
hollow, pothole, crevasse, ditch, convex, rift, crevice, fissure, cave, chasm, gully, grotto.

Usage examples for cavern

  1. I wished to follow her, and would have done so had not Montesinos recommended me not to take the trouble as it would be useless, particularly as the time was drawing near when it would be necessary for me to quit the cavern – The History of Don Quixote, Volume II., Complete by Miguel de Cervantes Saavedra
  2. He happened, one day, to be digging at the foot of a mountain, the spy of other mountains, that thrust its head above the clouds to see what they were doing up in the sky, and close to a cavern so deep and dark that the sun was afraid to enter it. – Stories from Pentamerone by Giambattista Basile
  3. Over these, folds of leaves well dried in the heat of the cavern – Papers from Overlook-House by Casper Almore