\ˈō-pən, -pᵊm\
opener\ˈōp-​nər, ˈō-​pə-​ \; openest\ˈōp-​nəst, ˈō-​pə-​ \

Definition of open 

(Entry 1 of 3)

1 : having no enclosing or confining barrier : accessible on all or nearly all sides cattle grazing on an open range

2a(1) : being in a position or adjustment to permit passage : not shut or locked an open door

(2) : having a barrier (such as a door) so adjusted as to allow passage the house was open

b : having the lips parted stood there with his mouth wide open

c : not buttoned or zipped an open shirt

3a : completely free from concealment : exposed to general view or knowledge their hostilities eventually erupted with open war

b : exposed or vulnerable to attack or question : subject open to doubt

c : being an operation or surgical procedure in which an incision is made such that the tissues are fully exposed

4a : not covered with a top, roof, or lid an open car her eyes were open

b : having no protective covering open wiring

5a : having the skin cracked, cut, or broken so that underlying tissue is exposed abrasions, lacerations, and other open wounds — see also open fracture

b of a head injury : marked by fracture or penetration of the skull

6 : not restricted to a particular group or category of participants open to the public open housing : such as

a : enterable by both amateur (see amateur sense 1) and professional (see professional entry 1 sense 2a) contestants an open tournament

b : enterable by a registered voter regardless of political affiliation an open primary

7 : fit to be traveled over : presenting no obstacle to passage or view the open road open country

8 : having the parts or surfaces laid out in an expanded position : spread out : unfolded an open book

9a(1) : low sense 13 an open vowel

(2) : formed with the tongue in a lower position Italian has an open and a close e

b(1) : having clarity and resonance unimpaired by undue tension or constriction of the throat an open vocal tone

(2) of a tone : produced by an open string or on a wind instrument by the lip without the use of slides, valves, or keys

10a : available to follow or make use of the only course open to us

b : not taken up with duties or engagements keep an hour open on Friday

c : not finally decided : subject to further consideration the salary is open an open question

d : available for a qualified applicant : vacant the job is still open

e : remaining available for use or filling until canceled an open order for more items

f : available for future purchase these items are in open stock

g : available for breeding : not now pregnant an open heifer

h computers : not proprietary : available to third party developers But while IBM pushes Notes, a proprietary technology created in the 1980s, a raft of new and much smaller rivals is plying the "open" technology of the 1990s: software on the World Wide Web, the fastest growing part of the Internet.— Bart Ziegler — compare open-source

11a : characterized by ready accessibility and usually generous attitude: such as

(1) : generous in giving

(2) : willing to hear and consider or to accept and deal with : responsive open to an offer open to suggestion

(3) : free from reserve or pretense : frank was open about his personal life

(4) of a relationship : not restricted to one partner at a time by mutual agreement — see also open marriage

b : accessible to the influx of new factors (such as foreign goods) an open market

12a : having openings, interruptions, or spaces open mesh : such as

(1) : being porous (see porous sense 2a) and friable open soil

(2) : sparsely distributed : scattered open population

(3) of a compound : having components (see component entry 1 sense 1) separated by a space in writing or printing (such as opaque projector)

b : not made up of a continuous closed circuit (see circuit entry 1 sense 2a) of channels the insect circulatory system is open

13a of an organ pipe : not stopped at the top

b of a string on a musical instrument : not stopped by the finger

14 : being in operation an open microphone especially : ready for business, patronage, or use the store is open from 9 to 5 the new highway will be open next week

15a(1) : characterized by lack of effective regulation of various commercial enterprises (see enterprise sense 2) an open town

(2) : not repressed (see repress sense 1) by legal controls open gambling

b : free from checking or hampering restraints an open economy

c : relatively unguarded by opponents passed to an open teammate

16 : having been opened by a first ante, bet, or bid the bidding is open

17 of punctuation : characterized by sparing use especially of the comma when possible without causing misinterpretation

18a : containing none of its endpoints an open interval

b : being a set or composed of sets each point of which has a neighborhood all of whose points are contained in the set the interior of a sphere is an open set

19a : being an incomplete electrical circuit

b : not allowing the flow of electricity an open switch

20 of a universe : having insufficient mass (see mass entry 2 sense 1c) to halt expansion gravitationally


opened\ˈō-​pənd, ˈō-​pᵊmd \; opening\ˈōp-​niŋ, ˈō-​pə-​ \

Definition of open (Entry 2 of 3)

transitive verb

1a : to move (something, such as a door) from a closed position

b : to make available for entry or passage by turning back (something, such as a barrier) or removing (something, such as a cover or an obstruction)

2a : to make available for or active in a regular function open a new store

b : to make accessible for a particular purpose opened new land for settlement

c : to initiate access to (a computer file) prior to use

3a : to disclose or expose to view : reveal

b : to make more discerning or responsive : enlighten must open our minds to the problems

c : to bring into view or come in sight of by changing position

4a : to make an opening in opened the boil

b : to loosen and make less compact open the soil

5 : to spread out : unfold opened the book

6a : to enter upon : begin opened the meeting

b : to commence action in a card game by making (a first bid), putting a first bet in (the pot), or playing (a card or suit) as first lead

7 : to restore or recall (something, such as an order) from a finally determined state to a state in which the parties are free to prosecute or oppose

intransitive verb

1 : to become open the office opened early

2a : to spread out : expand the wound opened under the strain

b : to become disclosed a beautiful vista opened before us

3 : to become enlightened or responsive

4 : to give access the rooms open onto a hall

5 : speak out sense 2 finally he opened freely on the subject

6a : to begin a course or activity

b : to make a bet, bid, or lead in commencing a round or hand of a card game

7 : to provide the opening performance of a show before the main event



Definition of open (Entry 3 of 3)

1 : opening

2 : open and unobstructed space: such as

a : open air

b : open water

3 : an open contest, competition, or tournament

4 : a public or unconcealed state or position

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Other Words from open


open adverb
openly \ˈō-​pən-​lē \ adverb
openness \ˈō-​pə(n)-​nəs \ noun


openability \ˌōp-​nə-​ˈbi-​lə-​tē, ˌō-​pə-​ \ noun
openable \ˈōp-​nə-​bəl, ˈō-​pə-​ \ adjective

Synonyms & Antonyms for open

Synonyms: Adjective

clear, cleared, free, unclogged, unclosed, unobstructed, unstopped

Synonyms: Verb


Synonyms: Noun

nature, open air, out-of-doors, outdoors, wild, wilderness

Antonyms: Adjective

blocked, clogged, closed, jammed, obstructed, plugged, shut, stopped, stuffed, uncleared

Antonyms: Verb

close, shut

Visit the Thesaurus for More 

Choose the Right Synonym for open


frank, candid, open, plain mean showing willingness to tell what one feels or thinks. frank stresses lack of shyness or secretiveness or of evasiveness from considerations of tact or expedience. frank discussions candid suggests expression marked by sincerity and honesty especially in offering unwelcome criticism or opinion. a candid appraisal open implies frankness but suggests more indiscretion than frank and less earnestness than candid. open in saying what they think plain suggests outspokenness and freedom from affectation or subtlety in expression. plain talk

liable, open, exposed, subject, prone, susceptible, sensitive mean being by nature or through circumstances likely to experience something adverse. liable implies a possibility or probability of incurring something because of position, nature, or particular situation. liable to get lost open stresses a lack of barriers preventing incurrence. a claim open to question exposed suggests lack of protection or powers of resistance against something actually present or threatening. exposed to infection subject implies an openness for any reason to something that must be suffered or undergone. all reports are subject to review prone stresses natural tendency or propensity to incur something. prone to delay susceptible implies conditions existing in one's nature or individual constitution that make incurrence probable. very susceptible to flattery sensitive implies a readiness to respond to or be influenced by forces or stimuli. unduly sensitive to criticism

Examples of open in a Sentence


The door suddenly swung open. You left the blinds wide open. The meat was roasted over an open fire. I was so tired that I couldn't keep my eyes open. Don't chew with your mouth open. staring with her eyes wide open There's already an open jar of pickles in the refrigerator. They kept the road open throughout the winter.


This door is hard to open. Open the door!” shouted the police officer. Would you mind if I opened a window? The car door opened and a beautiful woman stepped out. The door opened and closed so quietly that I didn't notice he had come in the room. This drawer is stuck. It just won't open! She comes home, turns on the TV, and starts opening her mail. She opened her eyes and smiled at me. I opened my umbrella and stepped out into the rain. Open your mouth wide for me,” said the dentist.


a daguerreotype of a cowboy whose face is roughened from a hard life in the open
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Recent Examples on the Web: Adjective

Dow’s own home and studio, completed in 1941, is open to the public. Allie Weiss, ELLE Decor, "5 Midcentury-Modern Landmarks You Need to See in the Midwest," 6 Dec. 2018 Starting next April, work will begin on a 33-gate Terminal One that will replace the existing Terminal A, the airport’s oldest terminal, which will remain open while the replacement is built. Barbara Peterson, Condé Nast Traveler, "New York's Airports Are Getting Billion-Dollar Makeovers—But What Will They Actually Change?," 21 Nov. 2018 That still leaves a substantial path for the tens of thousands of people who cross daily: Twenty-three lanes remain open at San Ysidro and 12 at Otay Mesa. Maria Verza, The Seattle Times, "US hardens border at Tijuana to prepare for migrant caravan," 13 Nov. 2018 Polls will remain open until at least 6 P.M. Find out when your local poll closes here, find your polling place. Stacey Leasca, Glamour, "Demi Lovato Just Returned to Instagram With an Important Message," 6 Nov. 2018 The national coffee chain, which operates all 365 days of the year in most locations, is just one of many stores that will remain open on the holiday. Jessica Leigh Mattern, Country Living, "Is Starbucks Open on Christmas?," 19 Oct. 2018 Most 24-hour stores should still remain open all day. Amina Lake Abdelrahman, Good Housekeeping, "These Stores Will Be Open on Thanksgiving Day," 9 Oct. 2018 Now, regular women looking to have babies are more open to it than ever. Danielle Mcnally, Marie Claire, "5 Women Get Candid About Why They Chose to Carry Someone Else’s Child," 1 Oct. 2018 When the operable walls are open, the house is full of sunlight. Liz Stinson, Curbed, "Sliding walls open this modern house to the outdoors," 7 Nov. 2018

Recent Examples on the Web: Verb

With designer Susan Alexandra, Antonoff is opening a pop-up shop this weekend at the Animal Haven shelter at 200 Centre Street. Steff Yotka, Vogue, "The Best Holiday Shopping Benefits Animal Adoption," 8 Dec. 2018 Purple felt very close to red, which felt like this heart-opening color, which is the whole point of the movie. Fawnia Soo Hoo, Glamour, "Why You Should Be Paying Attention to the Costumes in All Those Holiday Movies," 7 Dec. 2018 Plus, the hood is hinged at the front, opening away from you. Ezra Dyer, Popular Mechanics, "Five Very Important Questions About the 2019 Corvette ZR1," 6 Dec. 2018 Many traveled from family homes hours away to get in as soon as the town opened. Scott Wilson, The Seattle Times, "Nearly a month after the Camp Fire began razing their towns, Californians return to ruin," 5 Dec. 2018 This update: Adds RTT (real-time text) support for Wi-FI calling Adds a menu item to News for opening a story in Safari Resolves an issue that may prevent iTunes from playing media to third-party AirPlay speakers. Samuel Axon, Ars Technica, "Apple releases iOS 12.1.1, macOS Mojave 10.14.2, and tvOS 12.1.1," 5 Dec. 2018 In November, the brand launched an adorable kids' line called Brooklittles and opened a pop-up shop. Brittney Morgan, House Beautiful, "Brooklinen's New Pop-Up Shop Can Make Your Dream Bedroom A Reality," 4 Dec. 2018 On the latest episode of Recode Media, Shear said that watching something for two hours is different from repeatedly opening an app over two hours. Recode Staff, Recode, "Recode Daily: Black Friday shoppers chose their screens over brick-and-mortar stores," 26 Nov. 2018 This small speaker allows kids voice control with Alexa, opening the door to a ton of kid-friendly content (the speaker comes with a one-year subscription to FreeTime Unlimited). Alexandria Haslam, PCWorld, "Start stashing stocking stuffers early with these awesome Amazon Echo Dot deals," 5 Nov. 2018

Recent Examples on the Web: Noun

The whole space has an open, flowing layout, to encourage seamless wandering. Elise Taylor, Vogue, "A First Look at the Faena Bazaar, Miami Beach’s New Design Destination," 3 Dec. 2018 The Ropes Mansion is open between 12 p.m.-4 p.m. on weekends from May through late October. Alyssa Fiorentino, House Beautiful, "You Need To Know The Real Story Behind Allison's House From Hocus Pocus," 17 Oct. 2018 In the show's cold open, Kimmel presented Daniels with a Donald Trump puppet and urged her to show what Trump had done with it. Kelly Lawler, USA TODAY, "Stormy Daniels doesn't confirm or deny alleged Trump affair on 'Kimmel'," 31 Jan. 2018 In contrast to Carlsen’s noted ability to finish off end games, Caruana is said to intensely focus on the opens and search for an early edge. Andrew Beaton, WSJ, "Magnus Carlsen vs. the American in a Chess Championship for the Ages," 9 Nov. 2018 The Fake News Media, the true Enemy of the People, must stop the open & obvious hostility & report the news accurately & fairly. Stavros Agorakis, Vox, "Poll: GOP voters blame news for division in America; Democrats blame Trump," 1 Nov. 2018 Eat it here: Superdawg in Chicago (open until 1 a.m.); Curry 36 in Berlin (open until 5 a.m.); Bæjarins Beztu Pylsur in Reykjavík (open until 1 a.m.). Cnt Editors, Condé Nast Traveler, "A Debatable Encyclopedia of Drunk Food," 1 Oct. 2018 The Spy Who Loved Me’ In one of the most iconic cold opens of the franchise, 007 takes out a handful of would-be assassins while swooshing down the Austrian Alps. WSJ, "A Nearly Nude Take on James-Bond Style," 6 July 2018 The change will take effect before the open of trading next Tuesday. Bloomberg,, "Dow Jones industrial average is dumping General Electric and adding Walgreens," 19 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'open.' 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 open


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


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


13th century, in the meaning defined at sense 1

History and Etymology for open


Middle English, from Old English; akin to Old High German offan open, Old English ūp up


see open entry 1


see open entry 1

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Statistics for open

Last Updated

12 Dec 2018

Look-up Popularity

Time Traveler for open

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

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More Definitions for open



Financial Definition of open

What It Is

In the stock markets, open refers to the beginning of the trading day or the price of a security at the beginning of the trading day.

How It Works

The New York Stock Exchange has the most famous opening bell. At 9:30 am Eastern time, it rings. At that time, the last trading price for each security on the exchange the day before (the closing price) becomes the opening price, or the open.

Why It Matters

The open is the start of a new day, though it is important to note that that doesn't necessarily mean trading hasn't been going on right before the open. After-hours markets remain open as do other exchanges in other countries and time zones, which provides opportunity for the price to change right up until the open in many cases.

Source: Investing Answers



English Language Learners Definition of open

 (Entry 1 of 2)

: to move (a door, window, etc.) so that an opening is no longer covered

: to move and no longer cover an opening

: to cause (something) to no longer be covered, sealed, or blocked



English Language Learners Definition of open (Entry 2 of 2)

: a competition (such as a major golf tournament or tennis tournament) that allows both professionals and amateurs to participate

the open : an area or place without walls, barriers, etc. : an area or place that is not covered or enclosed

: a situation in which something (such as a feeling) is no longer hidden or kept secret


\ˈō-pən \

Kids Definition of open

 (Entry 1 of 3)

1 : not shut or blocked : not closed an open window open books

2 : not sealed, locked, or fastened an open zipper There's an open bottle of ketchup in the refrigerator.

3 : easy to enter, get through, or see open country

4 : ready to consider appeals or ideas an open mind

5 : not drawn together : spread out an open flower open umbrellas

6 : not enclosed or covered an open boat an open fire

7 : not secret : public They have an open dislike for one another.

8 : to be used, entered, or taken part in by all an open meeting It was an open race—any number of dogs could be entered.— John Reynolds Gardiner, Stone Fox

9 : not decided or settled an open question

Other Words from open

openly adverb
openness noun


opened; opening

Kids Definition of open (Entry 2 of 3)

1 : to change or move from a shut condition Sit down and open a book. The door opened. She opened her eyes.

2 : to clear by or as if by removing something in the way Workers were sent to open a road blocked with snow.

3 : to make or become ready for use They plan to open a store. The office opens at eight.

4 : to give access The rooms open onto a hall.

5 : begin sense 1, start Police have opened an investigation. They opened fire on the enemy.

Other Words from open

opener \ˈō-​pə-​nər, ˈōp-​nər \ noun



Kids Definition of open (Entry 3 of 3)

: space that is not enclosed or covered : outdoors Some slept in a cabin while others slept in the open.

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\ˈō-pən \

Medical Definition of open 

(Entry 1 of 2)

1a : not covered, enclosed, or scabbed over an open lesion an open running ulcer

b : not involving or encouraging a covering (as by bandages or overgrowth of tissue) or enclosure open treatment of burns

c : relating to or being a compound fracture

d : being an operation or surgical procedure in which an incision is made such that the tissues and organs are fully exposed — compare open-heart

2 : shedding the infective agent to the exterior open tuberculosis — compare closed sense 3

3a : unobstructed by congestion or occlusion open sinuses

b : not constipated open bowels

4 : using a minimum of physical restrictions and custodial restraints on the freedom of movement of the patients or inmates an open psychiatric ward


opened; opening

Medical Definition of open (Entry 2 of 2)

transitive verb

1a : to make available for entry or passage by removing (as a cover) or clearing away (as an obstruction)

b : to free (a body passage) of congestion or occlusion an inhalator for opening congested nasal passages open clogged arteries

2 : to make one or more openings in opened the boil

intransitive verb

: to spread out the wound opened



Legal Definition of open 

(Entry 1 of 2)

1 : exposed to general view or knowledge : free from concealment an open, notorious, continuous, and adverse use of the property an open and obvious danger

Note: When a defect, hazard, or condition is open such that a reasonable person under the circumstances should have recognized the danger posed by it, a defendant is usually relieved of liability for failure to warn.

2 : not restricted to a particular group or category of participants specifically : enterable by a registered voter regardless of political affiliation an open primary

3a : being in effect or operation an open mine a bench warrant still open

b : available for use an open toll road

c : not finally determined, decided, or settled : subject to further consideration an open question

d : remaining effective or available for use until canceled an open insurance contract

4 : not repressed or regulated by legal controls a state with open gambling


opened; opening

Legal Definition of open (Entry 2 of 2)

transitive verb

1 : to begin the process of open the succession

2a : to make the statement by which the trial of (a case) is begun and put before the court

b : to be the first to speak in summing up or arguing (a case)

3 : to restore or recall (as an order, rule, or judgment) from a finally determined state to a state in which the parties are free to prosecute or oppose by further proceedings

intransitive verb

1 : to begin action : commence on some course or activity the stock opened at par

2 : to begin the trial of a case defendant…has the option of presenting an opening statement immediately after plaintiff opens— J. H. Friedenthal et al.

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More from Merriam-Webster on open

Thesaurus: All synonyms and antonyms for open

Spanish Central: Translation of open

Nglish: Translation of open for Spanish Speakers

Britannica English: Translation of open for Arabic Speakers

Comments on open

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


a soft lustrous wool fabric with mohair

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