neck bone vs axis

neck bone and axis both are nouns.

Word	Noun	Adjective	Verb	Adverb
neck bone	Yes	No	No	No
axis	Yes	No	No	No

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

Other hyponyms of neck bone include atlas, atlas vertebra, axis vertebra.

neck bone (noun)	axis (noun)
one of 7 vertebrae in the human spine located in the neck region	the center around which something rotates
	the 2nd cervical vertebra; serves as a pivot for turning the head
	a straight line through a body or figure that satisfies certain conditions
	a group of countries in special alliance
	the main stem or central part about which plant organs or plant parts such as branches are arranged