36. back to bring (a stream of traffic) to a standstill.
37. back to accumulate or become clogged due to a stoppage.
38. back to copy (a computer file or program) as a precaution against failure.
39. (adj.)back situated at or in the rear: the back door.
40. back far away or removed from the front or main area, position, or rank; remote: back streets.
41. back of or belonging to the past: back issues of a magazine.
42. back in arrears; overdue: back pay.
43. back coming or going back; moving backward: back current.
44. back (of a speech sound) articulated with the tongue in the back part of the mouth, as either of the sounds of go.
45. back to trim the sails of a boat so that the wind strikes them first on the forward and then on the after side.
46. back to change one's opinion or position; vacillate.
47. back be (flat) on one's back, to be ill, helpless, or overcome by circumstances.
48. back behind one's back, without one's knowledge, esp. treacherously or secretly.
49. back break the back of, to conquer the most difficult or resistant part of: to break the back of urban crime.
50. back get one's back up, to become annoyed; take offense.
51. back have one's back to the wall, to be in a difficult or hopeless situation.
52. back (in) back of, at the rear of; behind.
53. back Informal. nagging or criticizing someone.
54. (adv.)back at, to, or toward the rear; backward: to step back.
55. back in or toward the past: to look back on one's youth.
56. back at or toward the original starting point, place, or condition: to go back to one's home town; to put a coat back on.
57. back in direct payment or return: to pay back a loan; to answer back.
58. back in a state of restraint or retention: to hold back tears; to hold back salary.
59. back in a reclining position: to lean back; to lie back.
60. back go back on,
61. back to fail to keep; renege on: to go back on a promise.
62. back to be faithless to; betray.
63. back backward and forward; to and fro.
64. back from side to side.
65. back from one to the other.
Etymology: (1480–90; aph. form of aback)
Definition of 'BACK'
Princeton's WordNet
1. (noun)back, dorsum the posterior part of a human (or animal) body from the neck to the end of the spine "his back was nicely tanned"
2. (noun)rear, back the side that goes last or is not normally seen "he wrote the date on the back of the photograph"
3. (noun)back, rear 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"
4. (noun)back (football) a person who plays in the backfield
5. (noun)spinal column, vertebral column, spine, backbone, back, rachis the series of vertebrae forming the axis of the skeleton and protecting the spinal cord "the fall broke his back"
6. (noun)binding, book binding, cover, back the protective covering on the front, back, and spine of a book "the book had a leather binding"
7. (noun)back the part of a garment that covers the back of your body "they pinned a `kick me' sign on his back"
8. (noun)back, backrest a support that you can lean against while sitting "the back of the dental chair was adjustable"
9. (adj)back (American football) the position of a player on a football team who is stationed behind the line of scrimmage
10. (adj)back(a) related to or located at the back "the back yard"; "the back entrance"
11. (adj)back(a), hind(a), hinder(a) located at or near the back of an animal "back (or hind) legs"; "the hinder part of a carcass"
12. (verb)back(a) of an earlier date "back issues of the magazine"
13. (verb)back, endorse, indorse, plump for, plunk for, support be behind; approve of "He plumped for the Labor Party"; "I backed Kennedy in 1960"
14. (verb)back travel backward "back into the driveway"; "The car backed up and hit the tree"
15. (verb)second, back, endorse, indorse give support or one's approval to "I'll second that motion"; "I can't back this plan"; "endorse a new project"
16. (verb)back cause to travel backward "back the car into the parking spot"
17. (verb)back support financial backing for "back this enterprise"
18. (verb)back be in back of "My garage backs their yard"
19. (verb)bet on, back, gage, stake, game, punt place a bet on "Which horse are you backing?"; "I'm betting on the new horse"
20. (verb)back shift to a counterclockwise direction "the wind backed"
21. (verb)back, back up establish as valid or genuine "Can you back up your claims?"
22. (adverb)back strengthen by providing with a back or backing
23. (adverb)back in or to or toward a former location "she went back to her parents' house"
24. (adverb)back, backward, backwards, rearward, rearwards 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"
25. (adverb)back in or to or toward an original condition "he went back to sleep"
26. (adverb)back, backward in or to or toward a pasttime "set the clocks back an hour"; "never look back"; "lovers of the past looking fondly backward"
27. (adverb)back in reply "he wrote back three days later"
28. (adverb)back 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"
1. (adverb)back toward the rear or away from to step back from the edge; to sit/lie back
2. back indicates a return to a previous state or position Put it back where it belongs.; She nursed him back to good health.; When will you be back home?
3. back in a reply Write back soon.; Call me back tomorrow.
4. back in or into the past back in 1964; thinking back to his childhood
5. (noun)back the part of the body between the neck and buttocks to lie on your back
6. back the part away from the front in the back of the room; on the back of the book; This last piece fits in the back.
7. back out back at the rear of a house a beautiful yard out back
8. back in back of behind boxes sitting in back of the door
9. back have your back to the wall to be in a situation that is difficult to get out of We had our backs to the wall early in the negotiations.
10. back in the back of your mind bothering you slightly when you think of it In the back of my mind, I knew something was missing.
11. back on sb's back constantly reminding or criticizing sb My manager is always on my back.
12. back when sb's back is turned when sb is not there to hear I know you talk about me when my back is turned.
13. (adjective)back away from the front the back pockets of his jeans; in the back row of seats
14. back from earlier back pay
15. (verb)back to give support to Many celebrities are backing the project.
16. back to move backward to back the car out of the driveway; He backed slowly away from the dog.
17. back to bet money on to back the winning horse
Definition of 'BACK'
Webster Dictionary
1. (adj)BACK being at the back or in the rear; distant; remote; as, the back door; back settlements
2. (adj)BACK being in arrear; overdue; as, back rent
3. (adj)BACK moving or operating backward; as, back action
4. (adverb)BACK in, to, or toward, the rear; as, to stand back; to step back
5. (adverb)BACK to the place from which one came; to the place or person from which something is taken or derived; as, to go back for something left behind; to go back to one's native place; to put a book back after reading it
6. (adverb)BACK to a former state, condition, or station; as, to go back to private life; to go back to barbarism
8. (adverb)BACK away from contact; by reverse movement
9. (adverb)BACK in concealment or reserve; in one's own possession; as, to keepback the truth; to keep back part of the money due to another
10. (adverb)BACK in a state of restraint or hindrance
11. (adverb)BACK in return, repayment, or requital
12. (adverb)BACK in withdrawal from a statement, promise, or undertaking; as, he took back0 the offensivewords
13. (adverb)BACK in arrear; as, to be back in one's rent
14. (noun)BACK a large shallow vat; a cistern, tub, or trough, used by brewers, distillers, dyers, picklers, gluemakers, and others, for mixing or cooling wort, holding water, hot glue, etc
16. (noun)BACK in human beings, the hinder part of the body, extending from the neck to the end of the spine; in other animals, that part of the body which corresponds most nearly to such part of a human being; as, the back of a horse, fish, or lobster
17. (noun)BACK an extended upper part, as of a mountain or ridge
18. (noun)BACK the outward or upper part of a thing, as opposed to the inner or lower part; as, the back of the hand, the back of the foot, the back of a hand rail
19. (noun)BACK the part opposed to the front; the hinder or rear part of a thing; as, the back of a book; the back of an army; the back of a chimney
20. (noun)BACK the part opposite to, or most remote from, that which fronts the speaker or actor; or the part out of sight, or not generally seen; as, the back of an island, of a hill, or of a village
21. (noun)BACK the part of a cutting tool on the opposite side from its edge; as, the back of a knife, or of a saw
Definitions of BACK 
Afrikaans: rug
Arabic: ظَهْر
Bulgarian: гръб
Brazilian: costas
Czech: záda
German: der Rücken
Danish: ryg
Greek: πλάτη
Spanish: espalda
Estonian: selg
Farsi: پشت؛ کمر
Finnish: selkä
French: dos
Hebrew: גַּב
Hindi: पीठ
Croatian: leđa
Hungarian: hát
Indonesian: punggung
Icelandic: bak, hryggur
Italian: schiena
Japanese: 背中
Korean: (사람의) 등
Lithuanian: nugara
Latvian: mugura
Malay: belakang
Dutch: rug
Norwegian: rygg
Polish: plecy
Persian: پشت؛ کمر
Pashto: شا، څټ
Portuguese: costas
Romanian: spate
Russian: спина
Slovak: chrbát
Slovenian: hrbet
Serbian: leđa
Swedish: rygg
Thai: หลัง
Turkish: sırt, arka
Taiwanese: （人）背部
Ukrainian: спина
Urdu: کمر، پُشت
Vietnamese: cái lưng
Chinese: （人）背部
