Meaning

• A small valley between mountains.

  "He built himself a cabin in a hollow high up in the Rockies."

• A sunken area or unfilled space in something solid; a cavity, natural or artificial.

  "the hollow of the hand or of a tree"

• A sunken area.

• A feeling of emptiness.

  "a hollow in the pit of one's stomach"

Meaning

• To make a hole in something; to excavate