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."