cavern

/ˈkæv.ən/noun

A cave of great size.

Example sentences

“The tour led us deep into a cavern filled with glittering rock formations.”
“Our voices echoed through the huge underground cavern.”

Grander and more literary than 'cave'. The adjective 'cavernous' describes any huge, echoing interior space.

Related words

boulderA very big rock that sits apart from the ground around it.caveA big natural hollow space underground or in the side of a cliff or hill.gravelSmall loose pieces of stone, often spread on paths, roads, and railway beds.slopeA stretch of ground that rises or falls at a steady angle.sandTiny loose grains of worn-down rock, finer than gravel, found on beaches and in deserts and used in building.ridgeA long, narrow raised line or strip along a surface, such as the top of a hill or a raised edge.