Definition of "Back" :
noun: (American football) the position of a player on a football team who is stationed behind the line of scrimmage
noun: a support that you can lean against while sitting
"The back of the dental chair was adjustable."
noun: the part of a garment that covers the back of your body
"They pinned a kick me' sign on his back."
noun: the protective covering on the front, back, and spine of a book
noun: the side that goes last or is not normally seen
"He wrote the date on the back of the photograph."
noun: the posterior part of a human (or animal) body from the neck to the end of the spine
"His back was nicely tanned."
noun: the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
"The fall broke his back."
noun: the part of something that is furthest from the normal viewer
"He stood at the back of the stage."
noun: (football) a person who plays in the backfield
verb: strengthen by providing with a back or backing
verb: establish as valid or genuine
"Can you back up your claims?."
verb: shift to a counterclockwise direction
"The wind backed."
verb: place a bet on
"Which horse are you backing?."
verb: travel backward
"Back into the driveway."
verb: cause to travel backward
"Back the car into the parking spot."
verb: support financial backing for
"Back this enterprise."
verb: be behind; approve of
"I backed Kennedy in 1960."
verb: give support or one's approval to
"I can't back this plan."
verb: be in back of
"My garage backs their yard."
adjective: located at or near the back of an animal
"Back (or hind) legs."
adjective: related to or located at the back
"The back yard."
adjective: of an earlier date
"Back issues of the magazine."
adverb: in or to or toward a past time
"Set the clocks back an hour."
adverb: at or to or toward the back or rear
"He moved back."
adverb: in repayment or retaliation
"We paid back everything we had borrowed."
adverb: in or to or toward a former location
"She went back to her parents' house."
adverb: in or to or toward an original condition
"He went back to sleep."
adverb: in reply
"He wrote back three days later."