Caves are cavities of rock used for concealment. While fleeing into the wilderness, Nephi and his companions hid themselves in “the cavity of a rock” after Laban’s servants did not overtake them (1 Nephi 3:27).
Ether hid himself in “the cavity of a rock by day” and went forth by night to view what would come upon the people. While dwelling there, Ether made the remainder of his record, and later fled and hid again in the cavity of the rock when people sought to kill him (Ether 13:13-22).