formation vs rear

formation and rear both are nouns.

Word	Noun	Adjective	Verb	Adverb
formation	Yes	No	No	No
rear	Yes	Yes	Yes	No

As nouns, rear is a hyponym of formation; that is, rear is a word with a more specific, narrower meaning than formation:

Other hyponyms of formation include flight, military formation, backfield, secondary, line, line, center, centre, flank, wing, head.

formation (noun)	rear (noun)
the act of fabricating something in a particular shape	the side that goes last or is not normally seen
the act of forming or establishing something	the fleshy part of the human body that you sit on
creation by mental activity	the back of a military formation or procession
a particular spatial arrangement	the side of an object that is opposite its front
an arrangement of people or things acting as a unit	the part of something that is furthest from the normal viewer
(geology) the geological features of the earth
natural process that causes something to form

formation (adjective)	rear (adjective)
	located in or toward the back or rear

formation (verb)	rear (verb)
	construct, build, or erect
	stand up on the hind legs, of quadrupeds
	cause to rise up
	look after a child until it is an adult
	rise up