\ 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

Keep scrolling for more

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
See More

Recent Examples on the Web: Noun

Davies struggled early on the back nine with a double bogey at 11, and fell to even-par overall before four birdies in six holes put her back at the top of the leaderboard., "Robert Rock takes two-shot lead at Scottish Open," 14 July 2018 Running back Jay Ajayi is gone and replaced by 35-year-old Frank Gore, who has nearly 15,000 carries on his back. Dave Hyde,, "Hyde5: More, uh, motivation as Dolphins RBs, WRs, rated 31st," 12 July 2018 One of those neighbors made his way into the 79-year-old’s home and found her body face down just inside her front entryway with a kitchen knife still buried in her back and an unspecified number of stab wounds, the Houston Chronicle reported. Matthew Martinez, star-telegram, "Ex-con was on cocaine, PCP when ‘voices’ told him to kill his 79-year-old mom, Texas cops say," 12 July 2018 Cave divers often wear their compressed air tanks on the side of their body instead of on their backs. John Ismay, New York Times, "Why the Thailand Cave Rescue Was So Difficult: A Diver Explains," 10 July 2018 At the Farallones, 40-foot humpbacks were launching into the air, rotating in half pirouettes, then crashing into the sea on their backs. Tom Stienstra,, "Chart-buster times: salmon to whales, bears to bighorns," 8 July 2018 This news comes six days after the Sixers announced that second-round pick Shake Melton would miss the summer league with a stress fracture in his back. Keith Pompey,, "Sixers' Landry Shamet to miss rest of NBA Summer League with sprained ankle," 7 July 2018 With hair loss and an open wound on his back, fearful in nature and tick infested, the sweet 11-year-old Australian kelpie now has a second chapter in his time with AHS. Arizona Republic, azcentral, "Adopt a dog or cat from metro Phoenix shelters this week," 5 July 2018 After the first few days with their mother, newborn tamarins will spend most of their infancy in the care of their father, who ferries them on his back. Katherine J. Wu, Smithsonian, "The National Zoo’s Golden Lion Tamarins Delight Curators with the Delivery of Twins," 3 July 2018

Recent Examples on the Web: Adverb

The Rising goalie sold him on the franchise, as his opinion held much weight with their friendship dating back to their time with Orange County. Clevis Murray, azcentral, "Phoenix Rising's Chris Cortez enjoying big season, life in Arizona, 'Game of Thrones'," 13 July 2018 And back at his own business empire, Mr. Musk is spread alarmingly thin. John D. Stoll, WSJ, "Tesla’s Musk Needs to Find His Mary Barra," 13 July 2018 The planes moved back into the air space at 4:08 p.m., northwest of Jeju Island, and flew out at 4:32 p.m. Ryan Gaydos, Fox News, "Russian military planes violate South Korean air defense zone four times, report says," 13 July 2018 Ariana Grande is back at it again, blessing her fans with new music. Sara M Moniuszko, USA TODAY, "Watch: Ariana Grande declares 'God is a Woman' in new song and Twitter is worshipping it," 13 July 2018 Mitchell experienced this type of response to braids back in high school, showing just how deeply these negative attitudes towards hairstyles typically worn by black women actually run. Devon Abelman, Allure, "Model Salem Mitchell Is Sick of Black Women's Hairstyles Being Labeled "Ghetto"," 13 July 2018 Cuomo, meanwhile, expectedly secured the party’s nomination back in May. The two will officially face off on September 13. Gabriella Paiella, The Cut, "Cynthia Nixon Got Over 65,000 Signatures to Appear on the Primary Ballot," 13 July 2018 Crouch says he's received several job offers in the wake of the incident, but is still hoping to get his job back at Academy Sports. CBS News, "Sporting goods store chain fires manager NRA calls "hero"," 12 July 2018 But not before Merkel and other top officials in the German government had publicly fired back at Trump’s breakfast diatribe. Tessa Berenson/brussels, Time, "'NATO Is Much Stronger Now': Trump Claims Victory After Contentious Summit," 12 July 2018

Recent Examples on the Web: Adjective

The Mariners’ erstwhile ace has been dealing with lower back issues the last few outings since tweaking it in a workout in Baltimore. Ryan Divish, The Seattle Times, "Mariners place Felix Hernandez on the 10-day disabled list," 10 July 2018 Working with Milwaukee's assistant hitting coach Jason Lane in the batting cages, Lane told Gennett to change where his back foot landed at the end of his swing. Bobby Nightengale,, "How Scooter Gennett transformed from a Cincinnati Reds waiver claim into an All-Star," 10 July 2018 On the back side, someone had written in Sharpie a travel itinerary for a 23-hour Greyhound trip from McAllen to Phoenix, where his aunt lives. Pamela Ren Larson, azcentral, "Trump administration issues new asylum rules aimed at families arriving at border," 13 July 2018 Manning is clearly on the back side of his career, but this is a little much for a guy who played better late in the 2017 season and certainly didn't have much offensive support to lean on. 2. Nate Davis, USA TODAY, "'Madden NFL 19' player ratings: 9 head-turning observations include slight to Eli Manning," 12 July 2018 In East Baltimore last year, winds blew down a vacant house that stood over the back patio of Verna Strawder’s home. Tim Prudente,, "Collapse: The rise and deadly fall of a Baltimore rowhouse," 12 July 2018 The officer was taken to IU Health Methodist Hospital and treated for back injuries, Woodruff said. Vic Ryckaert, Indianapolis Star, "Lawrence officer hurt in crash with drunken-driving suspect," 11 July 2018 Ramírez whiffed seven batters, with back-to-back strikeouts in the first and fourth innings. Katherine Fominykh,, "Orioles ride rookie Yefry Ramírez to beat error-riddled Rangers, 1-0," 15 July 2018 The whole unit is supported by a metal beam that wraps around the pack’s periphery, creating a continuity between the back panel and hipbelt. Kelly Bastone, Outside Online, "The Best Women’s Backpacking Packs," 13 July 2018

Recent Examples on the Web: Verb

Almost every single rumored 2020 candidate in the Senate has backed Sen. Bernie Sanders’a Medicare-for-all bill. Dylan Scott, Vox, "The “pleasant ambiguity” of Medicare-for-all in 2018, explained," 2 July 2018 Several Democratic senators, including Heidi Heitkamp (N.D.), Joe Manchin (W.Va.), and Joe Donnelly (Ind.) also backed Gorsuch and are facing reelection in states that Trump won. Natasha Bach, Fortune, "How an Alaska Senator Could Make or Break Trump's Supreme Court Plans," 2 July 2018 Costello also backs expansion of health savings accounts and wants Medicare Savings Accounts currently available elsewhere in the country to be made available to seniors in Florida. Steven Lemongello,, "Congress District 6: Where 6 candidates stand on issues," 13 July 2018 Organizers for Northern Nights are backing a bill currently making its way to the State Senate, called AB 2020. Taylor Mims, Billboard, "Chalice Festival Sues Bureau of Cannabis Control as Weed-Centric Events Battle With Legalization," 13 July 2018 President Barack Obama backed legislation that would add protections throughout his two terms, failing to get much traction even when Democrats controlled Congress his first two years. Mike Hendricks, kansascity, "Firefighters protect us. Who protects them?," 13 July 2018 The Marlins offense backed Straily with a three-run fourth inning off right-hander Freddy Peralta. Matthew Defranks,, "Marlins beat Brewers in 12 innings in front of record-low crowd," 12 July 2018 Vicki Shabo, vice president for workplace policies and strategies with the National Partnership for Women & Families, who testified at Wednesday’s hearing, backs Sen. Gillibrand's bill., "Ivanka Trump Says She Wants To "Go Beyond Parental Leave"," 12 July 2018 And Collins has backed Planned Parenthood, which last year honored her for her fight against Obamacare repeal. Francine Kiefer, The Christian Science Monitor, "For women senators, court nomination touches a very personal issue," 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.

See More

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

Keep scrolling for more

Learn More about back

Dictionary Entries near back







backache brake

Statistics for back

Last Updated

17 Sep 2018

Look-up Popularity

Time Traveler for back

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

See more words from the same century

Keep scrolling for more

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

Keep scrolling for more



Legal Definition of back 

1 : being overdue or in arrears back rent

2 : being retroactive especially as compensation reinstated with back pay

Keep scrolling for more

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).


to make amends

Get Word of the Day daily email!

Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!