terra firma vs neck

terra firma and neck both are nouns.

Word	Noun	Adjective	Verb	Adverb
terra firma	Yes	No	No	No
neck	Yes	No	Yes	No

As nouns, neck is a hyponym of terra firma; that is, neck is a word with a more specific, narrower meaning than terra firma:

terra firma (noun)	neck (noun)
the solid part of the earth's surface	an opening in a garment for the neck of the wearer; a part of the garment near the wearer's neck
	a narrow part of an artifact that resembles a neck in position or form
	the part of an organism (human or animal) that connects the head to the rest of the body
	a cut of meat from the neck of an animal
	a narrow elongated projecting strip of land

terra firma (verb)	neck (verb)
	kiss, embrace, or fondle with sexual passion