\ˈbak \
plural backs

Definition of back 

(Entry 1 of 5)

1a(1) : the rear part of the human body especially from the neck to the end of the spine

(2) : the body considered as the wearer of clothes They were left with nothing but the clothes on their backs.

(3) : capacity for labor, effort, or endurance Put your back into it!

(4) : the back considered as the seat of one's awareness of duty or failings get off my back

(5) : the back considered as an area of vulnerability the police officer's partner always watches his back

b : the part of a lower animal (such as a quadruped) corresponding to the human back riding on the back of an elephant

c : spinal column She had surgery on her back.

d : spine sense 1c The title is on the book's back.

2a : the side or surface opposite the front or face I only saw him from the back. : the rear part the back of the head the back of the mirror also : the farther or reverse side wrote the number on the back of an envelope

b : something at or on the back for support back of a chair

c : a place away from the front sat in back

3 : a position in some games (such as football or soccer) behind the front line of players also : a player in this position a defensive back

4 informal : a swimming race in which swimmers use the backstroke She placed first in the 100-meter back.

back of one's hand or back of the hand

: a show of contempt

back of one's mind

: the part of one's mind where thoughts and memories are stored to be drawn on

behind one's back

: without one's knowledge talking about me behind my back

in back of

: behind One day, I was sitting in the tiny parlor in back of the store …— John McNulty



Definition of back (Entry 2 of 5)

1a : to, toward, or at the rear asked the crowd to move back

b : in or into the past : backward in time looking back on her youth an event back in the last century Back then, no one had ever heard of chronic fatigue syndrome. also : ago several years back met him in the street two days back

c : to or at an angle off the vertical leaned back on his chair

d(1) : under restraint He wanted to fight but his friends held him back. holding back a laugh

(2) : in a delayed or retarded condition Bad weather set the launch date back several days.

e : in an inferior or secondary position especially : behind a competitor in points or ranking finished three strokes back

2a : to, toward, or in a place from which a person or thing came She left home and never went back. put the book back

b : to or toward a former state went back to private life

c : in return or reply forgot to write back



Definition of back (Entry 3 of 5)

1a : being at or in the back back door

b : distant from a central or main area back roads

c of a speech sound : articulated at or toward the back of the oral passage : formed deep within the mouth back vowels

2 : having returned or been returned

3 : being in arrears : overdue is owed several months in back pay

4 : moving or operating backward : reverse back action with oars

5 : not current back issues of a magazine

6 golf : constituting the final 9 holes of an 18-hole course


backed; backing; backs

Definition of back (Entry 4 of 5)

transitive verb

1a : to support by material or moral assistance backing a candidate for governor often used with up back up a friend in a fight

b : substantiate often used with up needs to back up her argument with evidence

c : to assume financial responsibility for back a new company

d : to provide musical accompaniment for often used with up a singer backed up by a guitarist

2a : to cause to go back (see back entry 2 sense 1a) or in reverse back the car into the garage

b : to articulate (a speech sound) with the tongue farther back : to form deeper within the mouth

3a : to furnish with a rear part : to furnish with a back (see back entry 1 sense 2) back a skirt with stiff material

b : to be at the rear part of : to be at the back (see back entry 1 sense 2) of a row of garages back the building

intransitive verb

1 : to move backward backed into a parking space often used with up back up to give him some spaceLet's back up a little to clarify what we're saying.

2 of the wind : to shift counterclockwise — compare veer entry 1 sense 2

3 : to have the rear part facing in the direction of something The house backs onto a golf course.

back and fill

1 nautical : to manage the sails of a ship so as to keep it clear of obstructions as it floats down with the current of a river or channel

2 : to take opposite positions alternately : shilly-shally has been back and filling on the issue

back into

: to get into inadvertently backed into the antiques business


geographical name
\ˈbak \

Definition of Back (Entry 5 of 5)

river 605 miles (974 kilometers) long in Nunavut, Canada, rising along the border with the Northwest Territories and flowing east-northeast into the Arctic Ocean

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Other Words from back


backed \ ˈbakt \ adjective
backless \ ˈbak-​ləs \ adjective


backer \ ˈba-​kər \ noun

Synonyms & Antonyms for back

Synonyms: Noun

rear, reverse, tail

Synonyms: Adverb

backward (or backwards), rearward (also rearwards)

Synonyms: Adjective

aft, after, hind, hinder, hindmost, posterior, rear, rearward

Synonyms: Verb

abet, aid, assist, backstop, help, prop (up), support

Antonyms: Noun

face, forehead, forepart, front

Antonyms: Adverb

ahead, along, forth, forward, forwards, on, onward (also onwards)

Antonyms: Adjective

anterior, fore, forward, front, frontal

Antonyms: Verb


Visit the Thesaurus for More 

Choose the Right Synonym for back


support, uphold, advocate, back, champion mean to favor actively one that meets opposition. support is least explicit about the nature of the assistance given. supports waterfront development uphold implies extended support given to something attacked. upheld the legitimacy of the military action advocate stresses urging or pleading. advocated prison reform back suggests supporting by lending assistance to one failing or falling. refusing to back the call for sanctions champion suggests publicly defending one unjustly attacked or too weak to advocate his or her own cause. championed the rights of children

recede, retreat, retract, back mean to move backward. recede implies a gradual withdrawing from a forward or high fixed point in time or space. the flood waters gradually receded retreat implies withdrawal from a point or position reached. retreating soldiers retract implies drawing back from an extended position. a cat retracting its claws back is used with up, down, out, or off to refer to any retrograde motion. backed off on the throttle

Examples of back in a Sentence


She was carrying her little daughter on her back. She has a pain in the small of her back. I slapped him on his back to congratulate him. She stabbed him in the back. He was handcuffed with his hands behind his back. a bird with a spotted back riding on the back of a horse a comfortable chair with a padded back


The soldiers moved back from the front lines. The police asked the crowd to move back from the scene of the accident. He left his friends two miles back. She turned around and looked back toward him. a chapter beginning several pages back He left his home and never went back. It's time to go back home. She took the book off the shelf and forgot to put it back. In the opening chapter the author looks back on his youth. an event back in the last century


He keeps his wallet in his back pocket. We came in through the back entrance. We drove on the back roads instead of the main roads. The company owes him several months in back pay.


I'm backing him for President. She backed the winner of the race and won a lot of money. She backed her argument with written evidence. She backed the singer on the guitar. She backed into a parking space. She backed out of the garage. The dog kept growling but backed off cautiously. back a skirt with stiff material
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Recent Examples on the Web: Noun

Will Massachusetts, with its history of progressive politics, turn its back on this hateful legislation? Lynn Yaeger, Vogue, "The Midterm Elections Are Almost Here—What You Need to Know Now," 5 Nov. 2018 This is a serious warning to Americans of all stripes: To sit this election out would be like turning our backs on the struggle for equality itself, a fight that marches on. Marie Claire, "With One Week Until Election Day, the Boxers Share Advice and Insight," 30 Oct. 2018 They're meant to be hung on the wall, and have a hook installed on the back for easy hang-up (as well as a black fabric backing to keep your walls scratch and scuff-free. Brittney Morgan, House Beautiful, "You'll Lose Your Ship Over These Driftwood Skulls," 16 Oct. 2018 This isn’t about having to turn your back on your heart’s heritage. Bess Matassa, Teen Vogue, "Monthly Lovescopes September 2018," 1 Sep. 2018 His neighbors sit in the back with their walkers and collapsible grocery carts. City Bureau, Chicago Reader, "These candid photos capture how seniors are growing communities—while growing older—on the south side," 12 July 2018 The cut allows enough room for a muscular set of thighs and glutes, but like the Maloja, these shorts use a stretch panel across the lower back and hips to accommodate all kinds of movements and body shapes. Kelly Bastone, Outside Online, "Europeans Know How to Make Women's Mountain Bike Shorts," 29 June 2018 And in the unlikely event of a Russian attack, the easternmost members of NATO feel pretty confident that their allies would have their backs. Simon Shuster/tallinn, Time, "Trump Shakes Up NATO, but Eastern European Allies Aren't Stirred," 13 July 2018 His players were at his back, at the other end of the field, applauding their fans, commiserating with them, the mood proud but somber, stony faces and distant eyes. Rory Smith, New York Times, "Croatia Digs Deeper, Burying England’s World Cup Dreams," 12 July 2018

Recent Examples on the Web: Adverb

After all, even the most coddled, opulent bird will set you back less than a similar amount of steak or lamb will. Elizabeth G. Dunn And Matthew Kronsberg, WSJ, "The Battle for Thanksgiving Heats Up," 31 Oct. 2018 At the end of a long day, collapse into a king-size bed at the Mekong Angkor Palace that’ll set you back around $30 a night. Marissa Miller, Teen Vogue, "13 Dream Vacations to Add to Your Bucket List," 24 Oct. 2018 Hayabusa2 is also slated to collect a sample of Ryugu rock and send it back to Earth at the end of 2020 so that the pristine cosmic material can be analyzed by scientists directly. Megan Gannon,, "'Crazy' Rocky Surface of Asteroid Ryugu Revealed in MASCOT Lander Images," 13 Oct. 2018 According to the salon website, a styling session with Sonnie will set you back 150 pounds, or nearly $200, for the hour. Jenna Rosenstein, Harper's BAZAAR, "Princess Eugenie Tapped Salon Hairstylist Sonnie Jo for the Royal Wedding," 12 Oct. 2018 Daredevil, the first of Netflix’s interlinked Marvel Cinematic Universe shows, set the tone for those series’ street-level conflicts back in 2015. Samantha Nelson, The Verge, "Most Read," 12 Oct. 2018 One will set you back around $10 to $15 and is pain free and safer than sticking a pair of scissors up your nose (ouch!). Jenn Sinrich, SELF, "Facial Hair Removal Guide: How to Remove Every Unwanted Hair From Your Face," 10 Oct. 2018 The 6-foot-8 Anderson and 6-foot-10 Isner go way back, to their college days, Isner at Georgia, Anderson at Illinois. Howard Fendrich,, "Illinois alumnus Kevin Anderson beats John Isner in longest semifinal in Wimbledon history," 13 July 2018 In his last six starts dating back to June 13, the left-hander hasn't allowed more than two earned runs -- and he's allowed exactly one run in each of his last four. Steve Gardner, USA TODAY, "Fantasy baseball waiver wire: Pitchers to stash before the All-Star break," 13 July 2018

Recent Examples on the Web: Adjective

Going into Comic-Con through the back door, into the green room. Christopher Rosa, Glamour, "Nicole Maines Is the Superhero Television Needs Right Now," 17 Oct. 2018 The implant was reportedly built into a server’s Ethernet port, giving hackers a back door into the telecommunications company’s computer networks. Makena Kelly, The Verge, "Tampered Chinese Ethernet port used to hack ‘major US telecom,’ says Bloomberg report," 9 Oct. 2018 Greywind's relatives met with prosecutors afterward but left the courthouse through a back door and did not comment to reporters. Fox News, "Man acquitted in pregnant woman's slaying in North Dakota," 28 Sep. 2018 But no one uses the front door: Everyone goes in the breezeway or the back door or through the garage. Alexandra Lange, Curbed, "Meet the Hunters, Vermont’s modernist-house pioneers," 9 Aug. 2018 While everyone is going crazy over the deals at Amazon for Prime Day right now, Newegg is sneaking through the back door of the bargain basement with its FantasTech sale. Ian Paul, PCWorld, "Forget Amazon Prime Day, Newegg's got two great deals on FreeSync displays right now," 17 July 2018 Deputies said a man tried to break in through a back door of the escape room in Vancouver, Washington, which is located inside a strip mall. Ashley May, USA TODAY, "Robber breaks into escape room. Then, calls 911 because he can't get out," 13 July 2018 Vertonghen had been waiting at the back post for the corner to be delivered, and watched as the ball arced around the penalty area. Graham Dunbar, The Seattle Times, "World Cup headed goal like never before sparks Belgium win," 2 July 2018 Cavani continued his run and Suarez curled the pass to the back post while Portugal defender Raphael Guerreiro was watching. Tim Booth,, "Edinson Cavani scores twice as Uruguay ousts Cristiano Ronaldo and Portugal," 30 June 2018

Recent Examples on the Web: Verb

First-term Democratic Rep. Jacky Rosen ousted him, attacking him for backing last year’s Republican effort to repeal President Barack Obama’s health care law. Alan Fram, The Seattle Times, "GOP keeps Senate control for 2 more years, triumph for Trump," 7 Nov. 2018 While Fung claims to be pro-choice, he was also endorsed by the state’s Right to Life Committee; Raimondo, by contrast, has a solid pro-choice record and is backed by women’s rights groups. Jill Filipovic, Harper's BAZAAR, "Your State-by-State Guide to Women Running in the Midterms," 31 Oct. 2018 Everyone knows about how Saudi Arabia’s Public Investment Fund has backed companies like Uber. Theodore Schleifer, Recode, "On the eve of the Saudi economic summit, we’re about to see just how damaged they are in Silicon Valley," 23 Oct. 2018 Research backs him up: A study published in the journal Sleep found that even one night of sleep deprivation made patients more vulnerable to heat loss. Colleen Stinchcombe, Woman's Day, "Why Am I Always Cold?," 16 Oct. 2018 Fasting also has its share of clinical studies to back it up. Mark Barna, Discover Magazine, "Not So Fast," 24 Sep. 2018 Plus it's backed by a five-year warranty and Samsung's excellent Magician SSD management utility. Ian Paul, PCWorld, "Our top two 1TB SSDs just hit all-time-low prices on Amazon so go get before they sell out," 23 Aug. 2018 That said, this plan is not only restrictive, but it's backed by zero scientific research to support its long-term efficacy and safety! Jaclyn London, Ms, Rd, Cdn, Good Housekeeping, "6 Things You Need to Know Before Trying Whole30," 7 Aug. 2018 Schulhof was arrested around midnight on Aug. 26, 2017 after backing his car into a pole in a Glenbrook North parking lot, authorities said. Alexandra Kukulka,, "Court proceedings continue for former hall monitor charged with carrying gun on school property," 11 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'back.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of back


before the 12th century, in the meaning defined at sense 1a(1)


13th century, in the meaning defined at sense 1a


15th century, in the meaning defined at sense 1a


1548, in the meaning defined at transitive sense 1a

History and Etymology for back


Middle English, from Old English bæc; akin to Old High German bah back, Old Norse bak


Middle English bac, aphetic form of abak aback


Middle English, partly attributive use of bac, back back entry 1, partly derivative of back back entry 2


verbal derivative of back entry 1

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Dictionary Entries near back







backache brake

Statistics for back

Last Updated

12 Nov 2018

Look-up Popularity

Time Traveler for back

The first known use of back was before the 12th century

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More Definitions for back



English Language Learners Definition of back

 (Entry 1 of 4)

: the rear part of the body : the part of the body that is opposite to the stomach and chest and that goes from the neck to the top of the legs

: the part of an animal that is like a person's back

: the side or surface of something that is opposite the front or face : the rear side or surface of something



English Language Learners Definition of back (Entry 2 of 4)

: in, toward, or at the back or rear

: to, toward, or in the place where someone or something was previously

: in or into the past : backward in time



English Language Learners Definition of back (Entry 3 of 4)

: of or relating to the back : located at the back

: far from a central or main area

: not yet paid : owed from an earlier time



English Language Learners Definition of back (Entry 4 of 4)

: to give help to (someone)

: to bet on (someone or something)

: to provide evidence that supports (something)


\ˈbak \

Kids Definition of back

 (Entry 1 of 4)

1 : the rear part of the human body from the neck to the end of the spine : the upper part of the body of an animal

2 : the part of something that is opposite or away from the front part

3 : a player in a team game who plays behind the forward line of players

Other Words from back

backed \ ˈbakt \ adjective a high-backed chair



Kids Definition of back (Entry 2 of 4)

1 : to, toward, or at the rear The crowd moved back.

2 : in or to a former time, state, or place I started working here some years back. I'll be right back.

3 : under control I kept back my anger.

4 : in return or reply Please write back. Give me back my bike.

back and forth

1 : toward the back and then toward the front

2 : between two places or people They sailed back and forth across the lake.



Kids Definition of back (Entry 3 of 4)

1 : located at the back the back door

2 : far from a central or main area back roads

3 : not yet paid : overdue He owes back rent.

4 : no longer published back issues of a magazine


backed; backing

Kids Definition of back (Entry 4 of 4)

1 : to give support or help to : uphold Which candidate are you backing?

2 : to move back She backed out of the garage.

back down

: to stop arguing or fighting for something You just can't back down and let people say I told you so.— Oliver Butterworth, The Enormous Egg

back off

: to back down

back out

: to decide not to do something after agreeing to do it

Other Words from back

backer noun


\ˈbak \

Medical Definition of back 

1a : the rear part of the human body especially from the neck to the end of the spine

b : the corresponding part of a lower animal (as a quadruped)

c : spinal column

2 : the part of the upper surface of the tongue behind the front and lying opposite the soft palate when the tongue is at rest

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Legal Definition of back 

1 : being overdue or in arrears back rent

2 : being retroactive especially as compensation reinstated with back pay

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Comments on back

What made you want to look up back? Please tell us where you read or heard it (including the quote, if possible).


a private place of worship

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