Pothole/pit/shaft/well/vertical cave (aven/puț vertical)

A cave containing vertical or nearly vertical shafts open to the surface, commonly but not necessarily at the entrance. Aven is equivalent to the British term, pothole. Compare cenote; natural well; pothole. 3. (British.) A vertical extension from a shaft in a passage or chamber roof that tapers upward rather likes a very elongate cone.Syn: pot, fissure cave, natural well, sótano; gouffre, abîme, cenote