noun

a hole or depression in something.

a hollow at the base of a large tree

hole,pit,cavity,crater,trough,cave,cavern,depression,indentation,concavity,dent,dint,dip,dimple,dish,basin,niche,nook,cranny,recess

verb

form by making a hole.

a tunnel was hollowed out in a mountain range

gouge out,scoop out,dig out,cut out,excavate,channel