cave
n. countable B2 Upper Intermediate Oxford US //ˈkeɪv// cave
n. a large natural hole in the side of a hill or under the ground. You can usually walk inside it, and it is often dark and cool.
n. a natural underground chamber or series of chambers, typically with an opening in the side of a hill or cliff.
The hikers found a small cave to stay dry during the storm.
Explorers discovered ancient paintings deep inside the cave that had been hidden for thousands of years.
The limestone cave system extends for several miles beneath the forest floor, featuring intricate rock formations and underground rivers that remain largely unmapped by modern geologists.