[bak-uh n-fawrth, -fohrth, -uh nd-]


backward and forward; side to side; to and fro: a back-and-forth shuttling of buses to the stadium; the back-and-forth movement of a clock's pendulum.


unresolved argument or discussion.

Origin of back-and-forth

First recorded in 1605–15




the rear part of the human body, extending from the neck to the lower end of the spine.
the part of the body of animals corresponding to the human back.
the rear portion of any part of the body: the back of the head.
the whole body, with reference to clothing: the clothes on his back.
ability for labor; effort; endurance: He put his back into the task.
the part opposite to or farthest from the front; the rear part: the back of a hall.
the part that forms the rear of any object or structure: the back of a chair.
the part that covers the back: the back of a jacket.
the spine or backbone: The fall broke his back.
any rear part of an object serving to support, protect, etc.: the back of a binder.
Nautical, Aeronautics. the forward side of a propeller blade (opposed to facedef 20).
Aeronautics. the top part or upper surface of an aircraft, especially of its fuselage.
Bookbinding. the edge of a book formed where its sections are bound together.
the backs, grounds along the River Cam in back of certain colleges at Cambridge University in England: noted for their great beauty.
Architecture. extrados.
  1. the upper side of a joist, rafter, handrail, etc.
  2. the area of interior wall between a window stool and the floor.
Mining. the roof of a stope or drift.
  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)

to support, as with authority, influence, help, or money (often followed by up): to back a candidate; to back up a theory with facts.
to bet on: to back a horse in the race.
to cause to move backward (often followed by up): to back a car.
to furnish with a back: to back a book.
to lie at the back of; form a back or background for: a beach backed by hills.
to provide with an accompaniment: a singer backed by piano and bass.
to get upon the back of; mount.
to write or print on the back of; endorse; countersign.
Carpentry. to attach strips of wood to the upper edge of (a joist or rafter) to bring it to a desired level.
  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)

to go or move backward (often followed by up).
Nautical. (of wind) to change direction counterclockwise (opposed to veer).


situated at or in the rear: at the back door; back fence.
far away or removed from the front or main area, position, or rank; remote: back settlements.
belonging to the past: back files; back issues.
in arrears; overdue: back pay.
coming or going back; moving backward: back current.
Navigation. reciprocal(def 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 Phrases

back away, to retreat; withdraw: They gradually began to back away from their earlier opinion.
back down, to abandon an argument, opinion, or claim; withdraw; retreat: He backed down as soon as a member of the audience challenged his assertion.
back off,
  1. to back down: Now that the time for action had arrived, it was too late to back off.
  2. reverse (the spindle) in mule spinning prior to winding on the newly spun length of yarn.
back out (of), to fail to keep an engagement or promise; withdraw from; abandon: Two entrants have backed out of competing in the marathon. You can't back out now.
back up,
  1. to bring (a stream of traffic) to a standstill: A stalled car backed up traffic for miles.
  2. print a sheet again on its other side.
  3. 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. duplicate (a file or a program) as a precaution against failure.
back up for, Australian Informal. to return for more of, as another helping of food.

Origin of back

before 1000; Middle English bak, Old English bæc back of the body; cognate with Old Frisian bek, Old Saxon, Old Norse bak; perhaps < Indo-European *bhogo- bending; cf. bacon
Related formsback·less, adjective
Can be confusedback up backup

Synonyms for back

Synonym study

31. 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.

Antonyms for back

1, 31. front.

Usage note

55. 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.




at, to, or toward the rear; backward: to step back.
in or toward the past: to look back on one's youth; They met in Chicago back in 1976.
at or toward the original starting point, place, or condition: to go back to the old neighborhood.
in direct payment or return: to pay back a loan; to answer back.
in a state of restraint or retention: to hold back the tears; to hold back salary.
in a reclining position: to lean back; to lie back.

Verb Phrases

go back on,
  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.

Origin of back

First recorded in 1480–90; aphetic variant of aback Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for back and forth




the posterior part of the human body, extending from the neck to the pelvisRelated adjective: dorsal
the corresponding or upper part of an animal
the spinal column
the part or side of an object opposite the front
the part or side of anything less often seen or usedthe back of a carpet; the back of a knife
the part or side of anything that is furthest from the front or from a spectatorthe back of the stage
the convex part of somethingthe back of a hill; the back of a ship
something that supports, covers, or strengthens the rear of an object
ball games
  1. a mainly defensive player behind a forward
  2. the position of such a player
the part of a book to which the pages are glued or that joins the covers
  1. the side of a passage or layer nearest the surface
  2. the earth between that level and the next
the upper surface of a joist, rafter, slate, tile, etc, when in positionCompare bed (def. 13)
at one's back behind, esp in support or pursuit
at the back of one's mind not in one's conscious thoughts
behind one's back without one's knowledge; secretly or deceitfully
break one's back to overwork or work very hard
break the back of to complete the greatest or hardest part of (a task)
on one's back or flat on one's back incapacitated, esp through illness
get off someone's back informal to stop criticizing or pestering someone
have on one's back to be burdened with
on someone's back informal criticizing or pestering someone
put one's back into to devote all one's strength to (a task)
put someone's back up or get someone's back up to annoy someone
see the back of to be rid of
back of beyond
  1. the back of beyonda very remote place
  2. Australianin such a place (esp in the phrase out back of beyond)
turn one's back on
  1. to turn away from in anger or contempt
  2. to refuse to help; abandon
with one's back to the wall in a difficult or desperate situation

verb (mainly tr)

(also intr) to move or cause to move backwards
to provide support, money, or encouragement for (a person, enterprise, etc)
to bet on the success ofto back a horse
to provide with a back, backing, or lining
to provide with a music accompanimenta soloist backed by an orchestra
to provide a background for; be at the back ofmountains back the town
to countersign or endorse
archaic to mount the back of
(intr; foll by on or onto) to have the back facing (towards)the house backs onto a river
(intr) (of the wind) to change direction in an anticlockwise direction in the northern hemisphere and a clockwise direction in the southernSee veer 1 (def. 3a)
nautical to position (a sail) so that the wind presses on its opposite side
back and fill
  1. nauticalto manoeuvre the sails by alternately filling and emptying them of wind to navigate in a narrow place
  2. to vacillate in one's opinion

adjective (prenominal)

situated behinda back lane
of the pastback issues of a magazine
owing from an earlier dateback rent
mainly US, Australian and NZ remoteback country
(of a road) not direct
moving in a backward directionback current
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


at, to, or towards the rear; away from something considered to be the front; backwards; behind
in, to, or towards the original starting point, place, or conditionto go back home; put the book back; my headache has come back
in or into the pastto look back on one's childhood
in reply, repayment, or retaliationto hit someone back; pay back a debt; to answer back
in checkthe dam holds back the water
in concealment; in reserveto keep something back; to hold back information
back and forth to and fro
back to front
  1. in reverse
  2. in disorder

Word Origin for back

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




a large tub or vat, esp one used by brewers

Word Origin for back

C17: from Dutch bak tub, cistern, from Old French bac, from Vulgar Latin bacca (unattested) vessel for liquids
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for back and forth



Old English bæc "back," from Proto-Germanic *bakam (cf. Old Saxon and Middle Dutch bak, Old Frisian bek), with no known connections outside Germanic.

The cognates mostly have been ousted in this sense in other modern Germanic languages by words akin to Modern English ridge (cf. Danish ryg, German Rücken). Many Indo-European languages show signs of once having distinguished the horizontal back of an animal (or a mountain range) from the upright back of a human. In other cases, a modern word for "back" may come from a word related to "spine" (Italian schiena, Russian spina) or "shoulder, shoulder blade" (Spanish espalda, Polish plecy).

To turn (one's) back on (someone or something) "ignore" is from early 14c. Behind (someone's) back "clandestinely" is from late 14c.

To know (something) like the back of one's hand, implying familiarity, is first attested 1893. The first attested use of the phrase is from a dismissive speech made to a character in Robert Louis Stevenson's "Catriona":

If I durst speak to herself, you may be certain I would never dream of trusting it to you; because I know you like the back of my hand, and all your blustering talk is that much wind to me.

The story, a sequel to "Kidnapped," has a Scottish setting and context, and the back of my hand to you was noted in the late 19th century as a Scottish expression meaning "I will have nothing to do with you" [e.g. "Jamieson's Dictionary of the Scottish Language"]. In English generally, the back of (one's) hand has been used to imply contempt and rejection since at least 1300. Perhaps the connection of a menacing dismissal is what made Stevenson choose that particular anatomical reference.



late 15c., "to move (something) back," from back (adv.). Meaning "to support" (as by a bet) is first attested 1540s. Related: Backed; backing.



Middle English, from back (n.) and back (adv.). Formerly with comparative backer (c.1400), also backermore. To be on the back burner in the figurative sense is from 1960, from the image of a cook keeping a pot there to simmer while he or she works on another concoction at the front of the stove.



late 14c., shortened from abak, from Old English on bæc "backwards, behind, aback" (see back (n.)). Back and forth attested from 1814.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for back and forth




The posterior portion of the trunk of the human body between the neck and the pelvis; the dorsum.
The backbone or spine.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Idioms and Phrases with back and forth

back and forth

Also, backward(s) and forward(s). To and fro, moving in one direction and then the opposite and so making no progress in either. For example, The clock pendulum swung back and forth. The term is also used figuratively, as in The lawyers argued the point backwards and forwards for an entire week. [c. 1600]


In addition to the idioms beginning with back

  • back against the wall
  • back alley
  • back and fill
  • back and forth
  • back away
  • back burner, on a
  • back door
  • back down
  • back in circulation
  • back in harness
  • back number
  • back of
  • back of beyond
  • back off
  • back of one's hand
  • back of one's mind
  • back on one's feet
  • back order
  • back out
  • back street
  • back the wrong horse
  • back to back
  • back to basics
  • back to the drawing board
  • back to the salt mines
  • back to the wall
  • back up
  • back water

also see:

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