a small valley between mountains; "he built himself a cabin in a hollow high up in the Appalachians"
a cavity or space in something; "hunger had caused the hollows in their cheeks"
as if echoing in a hollow space; "the hollow sound of footsteps in the empty ballroom"
not solid; having a space or gap or cavity; "a hollow wall"; "a hollow tree"; "hollow cheeks"; "his face became gaunter and more hollow with each year"
being or affecting or concerned with a surface; not deep or penetrating emotionally or intellectually; "superficial similarities"; "a superficial mind"; "his thinking was superficial and fuzzy"; "superficial knowledge"; "the superficial report didn't give the true picture"; "only superficial differences"
of little substance or significance; "a few superficial editorial changes"; "only trivial objections"
relating to a surface; "superficial measurements"; "the superficial area of the wall"