View synonyms for back



[ bak ]


  1. the rear part of the human body, extending from the neck to the lower end of the spine.
  2. the part of the body of animals corresponding to the human back.
  3. the rear portion of any part of the body:

    the back of the head.

  4. the whole body, with reference to clothing:

    the clothes on his back.

  5. ability for labor; effort or strength:

    He put his back into the task.

  6. the part opposite to or farthest from the front; the rear part:

    the back of a hall.

  7. the part that forms the rear of any object or structure:

    the back of a chair.

  8. the area directly behind a person:

    Face the town with the river at your back and follow the main street up the hill.

  9. the part that covers the back:

    the back of a jacket.

  10. the spine or backbone:

    The fall broke his back.

  11. any rear part of an object serving to support, protect, etc.:

    the back of a binder.

  12. Nautical, Aeronautics. the forward side of a propeller blade ( face, def 22 ).
  13. Aeronautics. the top part or upper surface of an aircraft, especially of its fuselage.
  14. Bookbinding. the edge of a book formed where its sections are bound together.
  15. the backs, grounds along the River Cam in back of certain colleges at Cambridge University in England: noted for their great beauty.
  16. Architecture. extrados.
  17. Carpentry.
    1. the upper side of a joist, rafter, handrail, etc.
    2. the area of interior wall between a window stool and the floor.
  18. Mining. the roof of a stope or drift.
  19. Sports.
    1. a player whose regular position is behind that of players who make initial contact with the opposing team, as behind the forward line in football or nearest the player's own goal in polo.
    2. the position occupied by this player.

verb (used with object)

  1. to support, as with authority, influence, help, or money (often followed by up ):

    to back a candidate;

    to back up a theory with facts.

    Synonyms: endorse, countenance, assist, favor, abet, sustain

  2. to bet on:

    to back a horse in the race.

  3. to cause to move backward (often followed by up ):

    to back a car.

  4. to furnish with a back:

    to back a book.

  5. to lie at the back of; form a back or background for:

    a beach backed by hills.

  6. to provide with an accompaniment:

    a singer backed by piano and bass.

  7. to get upon the back of; mount.
  8. to write or print on the back of; endorse; countersign.
  9. Carpentry. to attach strips of wood to the upper edge of (a joist or rafter) to bring it to a desired level.
  10. Nautical.
    1. to alter the position of (a sail) so that the wind will strike the forward face.
    2. to brace (yards) in backing a sail.
    3. to reinforce the hold of (an anchor) by means of a smaller one attached to it and dropped farther away.

verb (used without object)

  1. to go or move backward (often followed by up ).

    Synonyms: withdraw, retreat, retire

  2. Nautical. (of wind) to change direction counterclockwise ( veer ).


  1. situated at or in the rear:

    at the back door;

    back fence.

    Antonyms: front

  2. far away or removed from the front or main area, position, or rank; remote:

    back settlements.

  3. belonging to the past:

    back files;

    back issues.

  4. in arrears; overdue:

    back pay.

  5. coming or going back; moving backward:

    back current.

  6. Navigation. reciprocal ( def 7 ).
  7. Phonetics. (of a speech sound) produced with the tongue articulating in the back part of the mouth, as in either of the sounds of go.

verb phrase

  1. to abandon an argument, opinion, or claim; withdraw; retreat:

    He backed down as soon as a member of the audience challenged his assertion.

  2. Australian Informal. to return for more of, as another helping of food.
    1. to back down:

      Now that the time for action had arrived, it was too late to back off.

    2. Textiles. to reverse (the spindle) in mule spinning prior to winding on the newly spun length of yarn.
  3. to retreat; withdraw:

    They gradually began to back away from their earlier opinion.

  4. to fail to keep an engagement or promise; withdraw from; abandon: You can't back out now.

    Two entrants have backed out of competing in the marathon.

    You can't back out now.

    1. to bring (a stream of traffic) to a standstill:

      A stalled car backed up traffic for miles.

    2. Printing. to print a sheet again on its other side.
    3. Printing. to fill in (the thin copper shell of an electrotype) with metal in order to strengthen it.
    4. to move backward:

      Back up into the garage.

    5. to reinforce:

      We backed up the cardboard with slats so it wouldn't fall down.

    6. to support or confirm:

      He backed up my story and they let us go.

    7. Computers. to duplicate (a file or a program) as a precaution against failure.



[ bak ]


  1. at, to, or toward the rear; backward:

    to step back.

  2. in or toward the past:

    to look back on one's youth; They met in Chicago back in 1976.

  3. at or toward the original starting point, place, or condition:

    to go back to the old neighborhood.

  4. in direct payment or return:

    to pay back a loan; to answer back.

  5. in a state of restraint or retention:

    to hold back the tears; to hold back salary.

  6. in a reclining position:

    to lean back; to lie back.

verb phrase

    1. to be treacherous or faithless to; betray:

      to go back on friends.

    2. to fail to keep; renege on:

      to go back on promises.



[ bak ]


  1. a large tub, vat, or cistern used by dyers, brewers, distillers, etc., to hold liquids.
  2. a broad-beamed ferryboat hauled across a body of water by a rope or chain.



/ bæk /


  1. a large tub or vat, esp one used by brewers



/ bæk /


  1. the posterior part of the human body, extending from the neck to the pelvis dorsal
  2. the corresponding or upper part of an animal
  3. the spinal column
  4. the part or side of an object opposite the front
  5. the part or side of anything less often seen or used

    the back of a carpet

    the back of a knife

  6. the part or side of anything that is furthest from the front or from a spectator

    the back of the stage

  7. the convex part of something

    the back of a ship

    the back of a hill

  8. something that supports, covers, or strengthens the rear of an object
  9. ball games
    1. a mainly defensive player behind a forward
    2. the position of such a player
  10. the part of a book to which the pages are glued or that joins the covers
  11. mining
    1. the side of a passage or layer nearest the surface
    2. the earth between that level and the next
  12. the upper surface of a joist, rafter, slate, tile, etc, when in position Compare bed
  13. at one's back
    behind, esp in support or pursuit
  14. at the back of one's mind
    not in one's conscious thoughts
  15. behind one's back
    without one's knowledge; secretly or deceitfully
  16. break one's back
    to overwork or work very hard
  17. break the back of
    to complete the greatest or hardest part of (a task)
  18. on one's back or flat on one's back
    incapacitated, esp through illness
  19. get off someone's back informal.
    to stop criticizing or pestering someone
  20. have on one's back
    to be burdened with
  21. on someone's back informal.
    criticizing or pestering someone
  22. put one's back into
    to devote all one's strength to (a task)
  23. put someone's back up or get someone's back up
    to annoy someone
  24. see the back of
    to be rid of
  25. back of beyond
    1. a very remote place
    2. in such a place (esp in the phrase out back of beyond )
  26. turn one's back on
    1. to turn away from in anger or contempt
    2. to refuse to help; abandon
  27. with one's back to the wall
    in a difficult or desperate situation


  1. also intr to move or cause to move backwards
  2. to provide support, money, or encouragement for (a person, enterprise, etc)
  3. to bet on the success of

    to back a horse

  4. to provide with a back, backing, or lining
  5. to provide with a music accompaniment

    a soloist backed by an orchestra

  6. to provide a background for; be at the back of

    mountains back the town

  7. to countersign or endorse
  8. archaic.
    to mount the back of
  9. intr; foll by on or onto to have the back facing (towards)

    the house backs onto a river

  10. intr (of the wind) to change direction in an anticlockwise direction in the northern hemisphere and a clockwise direction in the southern See veer 1
  11. nautical to position (a sail) so that the wind presses on its opposite side
  12. back and fill
    1. nautical to manoeuvre the sails by alternately filling and emptying them of wind to navigate in a narrow place
    2. to vacillate in one's opinion


  1. situated behind

    a back lane

  2. of the past

    back issues of a magazine

  3. owing from an earlier date

    back rent

  4. remote

    back country

  5. (of a road) not direct
  6. moving in a backward direction

    back current

  7. phonetics of, relating to, or denoting a vowel articulated with the tongue retracted towards the soft palate, as for the vowels in English hard, fall, hot, full, fool


  1. at, to, or towards the rear; away from something considered to be the front; backwards; behind
  2. in, to, or towards the original starting point, place, or condition

    my headache has come back

    to go back home

    put the book back

  3. in or into the past

    to look back on one's childhood

  4. in reply, repayment, or retaliation

    pay back a debt

    to answer back

    to hit someone back

  5. in check

    the dam holds back the water

  6. in concealment; in reserve

    to hold back information

    to keep something back

  7. back and forth
    to and fro
  8. back to front
    1. in reverse
    2. in disorder

Discover More

Usage Note

Although some object to their use, the phrases in back of and the shorter—and much older— back of with the meaning “behind” are fully established as standard in American English: The car was parked ( in ) back of the house. Both phrases occur in all types of speech and writing.

Discover More

Other Words From

  • back·less adjective

Discover More

Word History and Origins

Origin of back1

First recorded before 1000; Middle English bak, Old English bæc “back of the body”; cognate with Old Frisian bek, Old Saxon, Old Norse bak; perhaps from Indo-European bhogo- (unattested) “bending”; bacon

Origin of back2

First recorded in 1480–90; shortening of aback

Origin of back3

First recorded in 1685–95; from Dutch bak “tub, trough,” from Late Latin bacca “water container”; compare French bac “ferryboat, punt”; basin

Discover More

Word History and Origins

Origin of back1

C17: from Dutch bak tub, cistern, from Old French bac , from Vulgar Latin bacca (unattested) vessel for liquids

Origin of back2

Old English bæc ; related to Old Norse bak , Old Frisian bek , Old High German bah

Discover More

Idioms and Phrases

  1. back and fill,
    1. Nautical. to trim the sails of a boat so that the wind strikes them first on the forward and then on the after side.
    2. to change one's opinion or position; vacillate.
  2. back and forth, South Midland U.S.
    1. to go back and forth, as in running errands or visiting:

      He spent the day back and forthing to the post office.

    2. to work in an aimless or ineffective way; expend effort with little result.
  3. back and forth, from side to side; to and fro; from one to the other:

    The pendulum of the grandfather clock swung back and forth.

  4. back water,
    1. Nautical. to reverse the direction of a vessel.
    2. to retreat from a position; withdraw an opinion:

      I predict that the council will back water on the tax issue.

  5. back yonder, Chiefly South Midland U.S. formerly; many years ago:

    Back yonder, when I was a boy, things were different.

  6. be flat on one's back,
    1. to be helpless or beaten:

      He's flat on his back after a long succession of failures.

    2. to be confined to one's bed because of illness.
  7. behind one's back, in one's absence; without one's knowledge; treacherously; secretly:

    I'd rather talk to him about it directly than discuss it behind his back.

  8. break someone's back, to cause a person to fail, especially to cause to become bankrupt:

    His family's extravagance is breaking his back.

  9. break the back of,
    1. to complete the principal or hardest part of (a project, one's work, etc.):

      He finally broke the back of the problem.

    2. to overcome; defeat:

      They broke the back of our union.

  10. get off one's back, Informal. to cease to find fault with or to disturb someone:

    The fight started when they wouldn't get off my back.

  11. get one's back up, Informal. to become annoyed; take offense:

    She gets her back up whenever someone mentions her family's influence.

  12. get / have someone’s back, Informal. to help and protect someone if necessary, especially in a time of trouble: Also have got someone's back.

    If he needs anything, I hope he knows I’ve got his back.

  13. have one's back to the wall, to be in a difficult or hopeless situation.
  14. in back of, behind: What could be in back of his strange behavior? Also back of.

    He hid in back of the billboard.

    What could be in back of his strange behavior?

  15. on someone's back, Informal. finding fault with or disturbing someone:

    The boss is always on my back about promptness.

  16. turn one's back on,
    1. to forsake or neglect:

      He was unable to turn his back on any suffering creature.

    2. to leave behind, as in anger.
  17. watch one’s back, Slang. to be on guard:

    Your assistant is gunning for your job—watch your back!

  18. a stab in the back. stab ( def 12 ).
  19. pat on the back. pat 1( defs 9, 11 ).
  20. stab (someone) in the back. stab ( def 13 ).

More idioms and phrases containing back

  • a while back
  • behind someone's back
  • break one's back
  • break the back of
  • call back
  • choke back
  • come back
  • cut back
  • double back
  • draw back
  • drop back
  • eyes in the back of one's head
  • fall back
  • fall back on
  • fall over (backward)
  • flat on one's back
  • from way back
  • get back
  • get one's back up
  • give the shirt off one's back
  • go back on one's word
  • hang back
  • hark(en) back
  • hold back
  • in one's own backyard
  • kick back
  • knock back
  • know like a book (the back of one's hand)
  • left-handed (back-handed) compliment
  • like water off a duck's back
  • look back
  • monkey on one's back
  • off someone's back
  • pat on the back
  • pay back in someone's own coin
  • pin someone's ears back
  • play back
  • plow back
  • pull back
  • put one's back in it
  • put one's back up
  • roll back
  • scratch someone's back
  • see the back of
  • set back
  • set back on one's heels
  • set one back
  • set the clock back
  • sit back
  • slap on the back
  • snap back
  • stab in the back
  • take aback
  • take a back seat
  • take back
  • talk back
  • think back
  • throw back
  • turn back
  • turn one's back on
  • when someone's back is turned
  • with one arm tied behind one's back
  • you scratch my back and I'll scratch yours

Discover More

Synonym Study

Back, hind, posterior, rear refer to something situated behind something else. Back means the opposite of front: back window. Hind, and the more formal word posterior, suggest the rearmost of two or more often similar objects: hind legs; posterior lobe. Rear is used of buildings, conveyances, etc., and in military language it is the opposite of fore: rear end of a truck; rear echelon.

Discover More

Example Sentences

Think back to the Bush-Kerry race of 2004, the Thrilla in Vanilla.

Back in New York, the slow pace and inward focus of her yoga practice was less fulfilling.

Music is a huge part of the tone of Black Dynamite overall—going back to the original 2009 movie on which the series is based.

The al Qaeda-linked gunmen shot back, but only managed to injure one officer before they were taken out.

So, Islamized teaching sends girls back home for marriage and housework, and remains exclusively for boys.

I waited three months more, in great impatience, then sent him back to the same post, to see if there might be a reply.

Ages back—let musty geologists tell us how long ago—'twas a lake, larger than the Lake of Geneva.

The boys were tumbling about, clinging to his legs, imploring that numerous things be brought back to them.

With a suffocating gasp, she fell back into the chair on which she sat, and covered her face with her hands.

She was holding the back of her chair with one hand; her loose sleeve had slipped almost to the shoulder of her uplifted arm.


Related Words

Definitions and idiom definitions from Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.