position vs back

position and back both are nouns.

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

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

position: (in team sports) the role assigned to an individual player
back: (American football) the position of a player on a football team who is stationed behind the line of scrimmage

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

position (noun)	back (noun)
the act of putting something in a certain place	(American football) the position of a player on a football team who is stationed behind the line of scrimmage
a job in an organization	the side that goes last or is not normally seen
(in team sports) the role assigned to an individual player	a support that you can lean against while sitting
the post or function properly or customarily occupied or served by another	the part of a garment that covers the back of your body
the act of positing; an assumption taken as a postulate or axiom	the protective covering on the front, back, and spine of a book
the spatial property of a place where or way in which something is situated	the posterior part of a human (or animal) body from the neck to the end of the spine
the arrangement of the body and its limbs	the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
a way of regarding situations or topics etc.	the part of something that is furthest from the normal viewer
a rationalized mental attitude	(football) a person who plays in the backfield
an opinion that is held in opposition to another in an argument or dispute
an item on a list or in a sequence
the particular portion of space occupied by something
a point occupied by troops for tactical reasons
the appropriate or customary location
the relative position or standing of things or especially persons in a society
a condition or position in which you find yourself

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

position (verb)	back (verb)
put into a certain place or abstract location	establish as valid or genuine
cause to be in an appropriate place, state, or relation	strengthen by providing with a back or backing
	shift to a counterclockwise direction
	place a bet on
	travel backward
	cause to travel backward
	support financial backing for
	be behind; approve of
	give support or one's approval to
	be in back of

position (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