cover vs back

cover and back both are nouns.

Word	Noun	Adjective	Verb	Adverb
cover	Yes	No	Yes	No
back	Yes	Yes	Yes	Yes

As nouns, cover and back are synonyms defined as:

cover and back: the protective covering on the front, back, and spine of a book

Other synonyms of cover include binding, book binding.

cover (noun)	back (noun)
the act of concealing the existence of something by obstructing the view of it	(American football) the position of a player on a football team who is stationed behind the line of scrimmage
fire that makes it difficult for the enemy to fire on your own individuals or formations	the side that goes last or is not normally seen
a false identity and background (especially one created for an undercover agent)	a support that you can lean against while sitting
a recording of a song that was first recorded or made popular by somebody else	the part of a garment that covers the back of your body
bedding that keeps a person warm in bed	the protective covering on the front, back, and spine of a book
a covering that serves to conceal or shelter something	the posterior part of a human (or animal) body from the neck to the end of the spine
covering for a hole (especially a hole in the top of a container)	the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
the protective covering on the front, back, and spine of a book	the part of something that is furthest from the normal viewer
a natural object that covers or envelops	(football) a person who plays in the backfield
a fixed charge by a restaurant or nightclub over and above the charge for food and drink

cover (adjective)	back (adjective)
	related to or located at the back
	of an earlier date
	located at or near the back of an animal

cover (verb)	back (verb)
sit on (eggs)	establish as valid or genuine
clothe, as if for protection from the elements	strengthen by providing with a back or backing
protect by insurance	shift to a counterclockwise direction
act on verbally or in some form of artistic expression	place a bet on
be responsible for reporting the details of, as in journalism	travel backward
maintain a check on; especially by patrolling	cause to travel backward
protect or defend (a position in a game)	support financial backing for
hold within range of an aimed firearm	be behind; approve of
play a higher card than the one previously played	give support or one's approval to
be responsible for guarding an opponent in a game	be in back of
provide with a covering or cause to be covered
form a cover over
copulate with a female, used especially of horses
cover as if with a shroud
put something on top of something else
travel across or pass over
hide from view or knowledge
spread over a surface to conceal or protect
be sufficient to meet, defray, or offset the charge or cost of
to take an action to protect against future problems
invest with a large or excessive amount of something
help out by taking someone's place and temporarily assuming his responsibilities
provide for
span an interval of distance, space or time
include in scope; include as part of something broader; have as one's sphere or territory
make up for shortcomings or a feeling of inferiority by exaggerating good qualities

cover (adverb)	back (adverb)
	at or to or toward the back or rear
	in or to or toward a past time
	in repayment or retaliation
	in or to or toward a former location
	in or to or toward an original condition
	in reply