hollow
adjective
°(of something solid) Having an empty space or cavity inside.
°(of a sound) Distant, eerie; echoing, reverberating, as if in a hollow space; dull, muffled; often low-pitched.
noun
°A small valley between mountains; "he built himself a cabin in a hollow high up in the Rockies".
°A sunken area in something solid.
verb
°to make a hole in something; to excavate.