axis vertebra vs axis

axis vertebra and axis both are nouns.

Word	Noun	Adjective	Verb	Adverb
axis vertebra	Yes	No	No	No
axis	Yes	No	No	No

As nouns, axis vertebra and axis are synonyms defined as:

axis vertebra and axis: the 2nd cervical vertebra; serves as a pivot for turning the head

axis vertebra (noun)	axis (noun)
the 2nd cervical vertebra; serves as a pivot for turning the head	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