Hollow is a term used to describe an EMPTY space or area, often with curved sides. The crossword solutions for this term include 'DIG' (3 letters), 'DEN' (3 letters), 'DEEP' (4 letters), 'GAP' (3 letters), 'DULL' (4 letters), 'DITCH' (5 letters), 'ARTIFICIAL' (10 letters), 'PIT' (3 letters), 'CAVE' (4 letters), 'DALE' (4 letters), 'DELL' (4 letters), 'DENT' (4 letters), 'GLEN' (4 letters), 'VAIN' (4 letters), 'VALE' (4 letters), 'EMPTY' (5 letters), 'FALSE' (5 letters), 'CAVITY' (6 letters), 'RAVINE' (6 letters), 'SUNKEN' (6 letters), 'VALLEY' (6 letters), 'gougeout' (8 letters), and 'emptyinthemiddle' (16 letters). All of these words are related to the concept of emptiness, either in terms of physical spaces or figurative meanings.