Noun

• S: (n) back (back%1:08:00::), dorsum (dorsum%1:08:01::) (the posterior part of a human (or animal) body from the neck to the end of the spine) "his back was nicely tanned"
• S: (n) rear (rear%1:06:00::), back (back%1:06:00::) (the side that goes last or is not normally seen) "he wrote the date on the back of the photograph"
• S: (n) back (back%1:15:02::), rear (rear%1:15:01::) (the part of something that is furthest from the normal viewer) "he stood at the back of the stage"; "it was hidden in the rear of the store"
• S: (n) back (back%1:18:00::) ((football) a person who plays in the backfield)
• S: (n) spinal column (spinal_column%1:08:00::), vertebral column (vertebral_column%1:08:00::), spine (spine%1:08:00::), backbone (backbone%1:08:00::), back (back%1:08:01::), rachis (rachis%1:08:00::) (the series of vertebrae forming the axis of the skeleton and protecting the spinal cord) "the fall broke his back"
• S: (n) binding (binding%1:06:00::), book binding (book_binding%1:06:00::), cover (cover%1:06:04::), back (back%1:06:03::) (the protective covering on the front, back, and spine of a book) "the book had a leather binding"
• S: (n) back (back%1:06:02::) (the part of a garment that covers the back of your body) "they pinned a `kick me' sign on his back"
• S: (n) back (back%1:06:01::), backrest (backrest%1:06:00::) (a support that you can lean against while sitting) "the back of the dental chair was adjustable"
• S: (n) back (back%1:04:00::) ((American football) the position of a player on a football team who is stationed behind the line of scrimmage)

Verb

• S: (v) back (back%2:41:00::), endorse (endorse%2:41:00::), indorse (indorse%2:41:00::), plump for (plump_for%2:41:00::), plunk for (plunk_for%2:41:00::), support (support%2:41:01::) (be behind; approve of) "He plumped for the Labor Party"; "I backed Kennedy in 1960"
• S: (v) back (back%2:38:00::) (travel backward) "back into the driveway"; "The car backed up and hit the tree"
• S: (v) second (second%2:41:00::), back (back%2:41:01::), endorse (endorse%2:41:02::), indorse (indorse%2:41:02::) (give support or one's approval to) "I'll second that motion"; "I can't back this plan"; "endorse a new project"
• S: (v) back (back%2:38:01::) (cause to travel backward) "back the car into the parking spot"
• S: (v) back (back%2:40:00::) (support financial backing for) "back this enterprise"
• S: (v) back (back%2:42:00::) (be in back of) "My garage backs their yard"
• S: (v) bet on (bet_on%2:33:00::), back (back%2:33:00::), gage (gage%2:33:00::), stake (stake%2:33:00::), game (game%2:33:00::), punt (punt%2:33:00::) (place a bet on) "Which horse are you backing?"; "I'm betting on the new horse"
• S: (v) back (back%2:30:03::) (shift to a counterclockwise direction) "the wind backed"
• S: (v) back (back%2:30:00::), back up (back_up%2:30:00::) (establish as valid or genuine) "Can you back up your claims?"
• S: (v) back (back%2:30:01::) (strengthen by providing with a back or backing)

Adjective

• S: (adj) back (back%3:00:00::) (related to or located at the back) "the back yard"; "the back entrance"
• S: (adj) back (back%3:00:00:posterior:00), hind (hind%3:00:00:posterior:00), hinder (hinder%3:00:00:posterior:00) (located at or near the back of an animal) "back (or hind) legs"; "the hinder part of a carcass"
• S: (adj) back (back%3:00:00:noncurrent:00) (of an earlier date) "back issues of the magazine"

Adverb

• S: (adv) back (back%4:02:04::) (in or to or toward a former location) "she went back to her parents' house"
• S: (adv) back (back%4:02:00::), backward (backward%4:02:03::), backwards (backwards%4:02:03::), rearward (rearward%4:02:00::), rearwards (rearwards%4:02:00::) (at or to or toward the back or rear) "he moved back"; "tripped when he stepped backward"; "she looked rearward out the window of the car"
• S: (adv) back (back%4:02:05::) (in or to or toward an original condition) "he went back to sleep"
• S: (adv) back (back%4:02:01::), backward (backward%4:02:02::) (in or to or toward a past time) "set the clocks back an hour"; "never look back"; "lovers of the past looking fondly backward"
• S: (adv) back (back%4:02:06::) (in reply) "he wrote back three days later"
• S: (adv) back (back%4:02:03::) (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"