The term 'HART PART' is a combination of two words, 'HART' and 'PART'. HART is an archaic word for a male deer, usually referring to a stag or buck. PART is a noun meaning a portion or division of something. Together, the two words form a phrase that can be interpreted as a metaphor for a male deer's antlers, which are a PART of the animal's body. The crossword solution for this term is 'ANTLER', a six-letter word referring to the branching horns of a deer.