n.

1. the posterior part of a human (or animal) body from the neck to the end of the spine;
   dorsum
   
   • his back was nicely tanned
2. the side that goes last or is not normally seen;
   rear
   
   • he wrote the date on the back of the photograph
3. the part of something that is furthest from the normal viewer;
   rear
   
   • he stood at the back of the stage
   • it was hidden in the rear of the store
4. (football) a person who plays in the backfield
5. the series of vertebrae forming the axis of the skeleton and protecting the spinal cord;
   spinal column, vertebral column, spine, backbone, rachis
   
   • the fall broke his back
6. the protective covering on the front, back, and spine of a book;
   binding, book binding, cover
   
   • the book had a leather binding
7. the part of a garment that covers the back of your body
   
   • they pinned a `kick me' sign on his back
8. a support that you can lean against while sitting;
   backrest
   
   • the back of the dental chair was adjustable
9. the position of a player on a football team who is stationed behind the line of scrimmage

v.

1. be behind; approve of;
   endorse, indorse, plump for, plunk for, support
   
   • He plumped for the Labor Party
   • I backed Kennedy in 1960
2. travel backward
   
   • back into the driveway
   • The car backed up and hit the tree
3. give support or one's approval to;
   second, endorse, indorse
   
   • I'll second that motion
   • I can't back this plan
   • endorse a new project
4. cause to travel backward
   
   • back the car into the parking spot
5. support financial backing for
   
   • back this enterprise
6. be in back of
   
   • My garage backs their yard
7. place a bet on;
   bet on, gage, stake, game, punt
   
   • Which horse are you backing?
   • I'm betting on the new horse
8. shift to a counterclockwise direction
   
   • the wind backed
9. establish as valid or genuine;
   back up
   
   • Can you back up your claims?
10. strengthen by providing with a back or backing

adj.

1. related to or located at the back;
   back(a)
   
   • the back yard
   • the back entrance
2. located at or near the back of an animal;
   back(a), hind(a), hinder(a)
   
   • back (or hind) legs
   • the hinder part of a carcass
3. of an earlier date;
   back(a)
   
   • back issues of the magazine

adv.

1. in or to or toward a former location
   
   • she went back to her parents' house
2. at or to or toward the back or rear;
   backward, backwards, rearward, rearwards
   
   • he moved back
   • tripped when he stepped backward
   • she looked rearward out the window of the car
3. in or to or toward an original condition
   
   • he went back to sleep
4. in or to or toward a past time;
   backward
   
   • set the clocks back an hour
   • never look back
   • lovers of the past looking fondly backward
5. in answer;
   in reply
   
   • he wrote back three days later
   • had little to say in reply to the questions
6. in repayment or retaliation
   
   • we paid back everything we had borrowed
   • he hit me and I hit him back
   • I was kept in after school for talking back to the teacher