cave

/keɪv/noun

A big natural hollow space underground or in the side of a cliff or hill.

Example sentences

“Bats flew out of the cave at dusk.”
“The children explored the dark cave with flashlights.”

Also a verb: to 'cave in' means to collapse, or figuratively to give up under pressure.

Related words

cavernA cave of great size.slopeA stretch of ground that rises or falls at a steady angle.boulderA very big rock that sits apart from the ground around it.ridgeA long, narrow raised line or strip along a surface, such as the top of a hill or a raised edge.gravelSmall loose pieces of stone, often spread on paths, roads, and railway beds.peakThe pointed top of a mountain, or a mountain with a pointed top.