Latin word cavum comes from Proto-Indo-European *ḱówH-

Detailed word origin of cavum

Dictionary entry	Language	Definition
*ḱówH-	Proto-Indo-European (ine-pro)
*ḱówHwos	Proto-Indo-European (ine-pro)
cavum	Latin (lat)	A cave, burrow, cavern. A hole, cavity, depression, pit, opening.