The term 'prefix with -gon' refers to a group of words that all have the same prefix, '-gon, ' and refer to a specific number of sides or angles. The solutions to this crossword are nona (4 letters), deca (4 letters), penta (5 letters), octa (4 letters), hexa (4 letters), and iso (3 letters). Nona means nine, deca means ten, penta means five, octa means eight, hexa means six, and iso means equal. All of these words refer to the number of sides or angles of a particular shape.