Adjective from Middle English open, from Old English open (“open”), from Proto-West Germanic *opan, from Proto-Germanic *upanaz (“open”), from Proto-Indo-European *upo (“up from under, over”). Cognates * Scots apen (“open”) * Saterland Frisian eepen (“open”) * West Frisian iepen (“open”) * Cimbrian offe (“open”) * Dutch open (“open”) * German offen (“open”) * Vilamovian ufa, uffa (“open”) * Yiddish אָפֿן (ofn, “open”) * Danish åben (“open”) * Icelandic opinn (“open”) * Norwegian Bokmål åpen (“open”) * Norwegian Nynorsk open (“open”) * Swedish öppen (“open”) Compare also Latin supinus (“on one's back, supine”), Albanian hap (“to open”). Related to up. Verb from Middle English openen, from Old English openian (“to open”), from Proto-West Germanic *opanōn, from Proto-Germanic *upanōną (“to raise; lift; open”), from Proto-Germanic *upanaz (“open”, adjective). Cognate with Saterland Frisian eepenje (“to open”), West Frisian iepenje (“to open”), Dutch openen (“to open”), German öffnen (“to open”), Danish åbne (“to open”), Swedish öppna (“to open”), Norwegian Bokmål åpne (“to open”), Norwegian Nynorsk and Icelandic opna (“to open”). Related to English up. Noun from Middle English open (“an aperture or opening”), from the verb. In the sports sense, however, a shortening of “open competition”.
Usually Able to have something pass through or along it.
Come in – the door's open.
The ice has cleared and the channel is open again.
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she had heard stories about him, flutters of talk through open doors.2025, Megan Hunter, Days of Light, Grove Atlantic:
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Usually Not covered, sealed, etc.; having an opening or aperture showing what is inside.
The jewellery box was lying open.
Don't just stand there with your mouth open!
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Along the street ran an open sewer.
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Usually Not physically drawn together, folded or contracted.
She greeted them with open arms.
The book was open at page 23.
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an open hand; an open flower; an open (loosely woven) fabric
Each, with open arms, embraced her chosen knight.1700, [John] Dryden, “The Flower and the Leaf: Or, The Lady in the Arbour. A Vision.”, in Fables Ancient and Modern; […], London: […] Jacob Tonson, […], →OCLC:
When the top sheet, blanket, and bedspread of a closed bed are turned back, or fanfolded, the closed bed becomes an open bed, or a bed ready to receive a patient or resident.2005, Pamela J. Carter, Susan Lewsen, Lippincott's Textbook for Nursing Assistants, page 277:
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Usually Of a space, free of objects and obstructions.
It was a large, open room.
Most of the site was occupied by huts, but there was an open area in the centre.
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Soon we left the forest behind and we were out in open country.
The open road, the dusty highway[…]1908 October, Kenneth Grahame, The Wind in the Willows, New York, N.Y.: Charles Scribner’s Sons, →OCLC:
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Medicine, SciencesUsually Resulting from an incision, puncture or any other process by which the skin no longer protects an internal part of the body.
an open fracture
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Proscribed, Sometimes, Usually Unlocked or unlatched but not physically open.
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Engineering, Natural sciences, Physical sciencesUsually, Of valve or damper In a position allowing fluid to flow.
Gas and liquid flow
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Usually Of a sandwich, etc.: composed of a single slice of bread with a topping.
open sandwich
Starry food is fun to make. You can buy bright yellow American mustard (which isn’t too strong!) in squeezy bottles and pipe stars on to hot dogs and open burgers or sandwiches.2001, Jennie Walters, Caz’s Birthday Blues (Party Girls), London: Hodder Children’s Books, →ISBN:
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When the burgers are ready, place them on the toasted rolls with the romaine lettuce leaves and top with the salsa. Serve as open burgers.2012, Jo McAuley, “[Meat and Poultry] Turkey Burgers with Spicy Salsa”, in Hamlyn QuickCook: Low Fat, London: Hamlyn, →ISBN, page 152:
Sunday morning in Wellow and we feast on open bagels with grilled ham, tomato and Swiss cheese, requested and highly praised.2015, Michael Robotham, chapter 17, in Close Your Eyes, London: Sphere, →ISBN, page 133:
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Regional, Usually Not of a quality to prevent communication, as by closing waterways, blocking roads, etc.; hence, not frosty or inclement; mild; used of the weather or the climate.
an open winter
He desires me to tell you that the present open weather induces him to accept Mr Vernon's invitation to prolong his stay in Sussex that they may have some hunting together.c. 1794, Jane Austen, Lady Susan:
› Able to be used or interacted with in some way.
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Available for use or operation.
Your bank account is now open.
Phone lines open at 10 pm.
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This is the only option open to us.
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Actively conducting or prepared to conduct business.
Banks are not open on bank holidays.
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Allowing entrance to visitors or the public.
I hereby declare this fete open.
The school has an open day on Saturday.
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Receptive.
I am open to new ideas.
Wherefore if Demetrius […] have a matter against any man, the law is open and there are deputies.1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Acts 19:38:
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A U.K. survey found attitudes toward public transit had been set back by two decades, with only 43% of drivers open to using their car less, even if public transport improves.2021 April 2, Ciara Nugent, “Can Public Transit Survive the Pandemic? London's New Transport Commissioner Wants You to Believe It Can”, in Time, archived from the original on 03 Apr 2021:
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With 'to' Susceptible or vulnerable (to the stated means).
open to question; open to attack; open to criticism
The service that I truly did his life, / Hath left me open to all injuries.c. 1596–1599 (date written), William Shakespeare, “The Second Part of Henry the Fourth, […]. Epilogue.”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene ii]:
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Computing, Engineering, Mathematics, Natural sciences, Physical sciences, SciencesUsually, Of a file In current use; connected to as a resource.
I couldn't save my changes because another user had the same file open.
You're getting short of memory because you have too many apps open.
› Not hidden or restricted.
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Not concealed; overt.
It is a blatant example of open criminality.
His thefts were too open.c. 1597 (date written), William Shakespeare, “The Merry Wiues of Windsor”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene iii]:
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That I may find him, and with secret gaze / Or open admiration him behold.1667, John Milton, “Book III”, in Paradise Lost. […], London: […] [Samuel Simmons], and are to be sold by Peter Parker […]; [a]nd by Robert Boulter […]; [a]nd Matthias Walker, […], →OCLC; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873, →OCLC:
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Of a person, not concealing their feelings, opinions, etc.; candid, ingenuous.
Nowadays people are more open about their sexuality.
1731-1735, Alexander Pope, Moral Essays with aspect open, shall erect his head
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The Moor is of a free and open nature.c. 1603–1604 (date written), William Shakespeare, “The Tragedie of Othello, the Moore of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene iii]:
The French are always open, familiar, and talkative.1705, J[oseph] Addison, Remarks on Several Parts of Italy, &c. in the Years 1701, 1702, 1703, London: […] Jacob Tonson, […], →OCLC:
Due to severe and pervasive discrimination, people dared not be open about their homosexuality, and because no one would be open, social prejudice and discrimination became even stronger.2001, Xiaopei He, “Chinese Queer (Tongzhi) Women Organizing in the 1990s”, in Ping-Chun Hsiung, Maria Jaschok, Cecilia Milwertz, Red Chan, editors, Chinese Women Organizing: Cadres, Feminists, Muslims, Queers, Berg, →ISBN, →LCCN, →OCLC, page 41:
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Public.
He published an open letter to the governor on a full page of The New York Times.
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LawOf correspondence Written or sent with the intention that it may made public or referred to at any trial, rather than by way of confidential private negotiation for a settlement.
You will observe that this is an open letter and we reserve the right to mention it to the judge should the matter come to trial.
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With open access, of open science, or both.
We hope that all aspects of the project will be open rather than paywalled.
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Computing, Education, Engineering, Mathematics, Natural sciences, Physical sciences, Sciences Made public, usable with a free licence and without proprietary components.
Since the launch early last year of […] two Silicon Valley start-ups offering free education through MOOCs, massive open online courses, the ivory towers of academia have been shaken to their foundations. University brands built in some cases over centuries have been forced to contemplate the possibility that information technology will rapidly make their existing business model obsolete.2013 July 20, “The attack of the MOOCs”, in The Economist, volume 408, number 8845:
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Hobbies, Lifestyle, Sports Of a tournament or competition, allowing anyone to enter, especially or originally irrespective of professional or amateur status.
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Games, Hobbies, Lifestyle, Sports Characterised by free-flowing play.
Compared to their last match, which was a dour and defensive affair, this was a very open game.
› Not completed or finalised.
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Not settled; not decided or determined; not withdrawn from consideration.
an open question
to keep an offer or opportunity open
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BusinessSometimes Not fulfilled or resolved; incomplete.
I've got open orders for as many containers of red durum as you can get me.
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Not having one end joined to the other; not forming a closed loop.
Mathematics, Sciences, TopologyOf a set Which is part of a predefined collection of subsets of X, that defines a topological space on X.
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Entertainment, Lifestyle, Music Of a note, played without pressing the string against the fingerboard.
Stringed instruments
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Entertainment, Lifestyle, Music Of a note, played without closing any finger-hole, key or valve.
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Human sciences, Linguistics, Phonetics, Phonology, Sciences Uttered with a relatively wide opening of the articulating organs; said of vowels.
"Supposing somebody sees you, with all those flowers too? Supposing somebody writes him a letter? Ooooh!" (a pure round open Tamil O.)1959, Anthony Burgess, Beds in the East (The Malayan Trilogy), published 1972, page 421:
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Human sciences, Linguistics, Phonetics, Phonology, Sciences Uttered, as a consonant, with the oral passage simply narrowed without closure.
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Computing, Engineering, Mathematics, Natural sciences, Physical sciences, SciencesUsed before "code" Source code of a computer program that is not within the text of a macro being generated.
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Of a multi-word compound Having component words separated by spaces, as opposed to being joined together or hyphenated; for example, time slot as opposed to timeslot or time-slot.
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Hobbies, Lifestyle, SportsEspecially Of a club, bat or other hitting implement, angled upwards and/or (for a right-hander) clockwise of straight.
Adjective from Middle English open, from Old English open (“open”), from Proto-West Germanic *opan, from Proto-Germanic *upanaz (“open”), from Proto-Indo-European *upo (“up from under, over”). Cognates * Scots apen (“open”) * Saterland Frisian eepen (“open”) * West Frisian iepen (“open”) * Cimbrian offe (“open”) * Dutch open (“open”) * German offen (“open”) * Vilamovian ufa, uffa (“open”) * Yiddish אָפֿן (ofn, “open”) * Danish åben (“open”) * Icelandic opinn (“open”) * Norwegian Bokmål åpen (“open”) * Norwegian Nynorsk open (“open”) * Swedish öppen (“open”) Compare also Latin supinus (“on one's back, supine”), Albanian hap (“to open”). Related to up. Verb from Middle English openen, from Old English openian (“to open”), from Proto-West Germanic *opanōn, from Proto-Germanic *upanōną (“to raise; lift; open”), from Proto-Germanic *upanaz (“open”, adjective). Cognate with Saterland Frisian eepenje (“to open”), West Frisian iepenje (“to open”), Dutch openen (“to open”), German öffnen (“to open”), Danish åbne (“to open”), Swedish öppna (“to open”), Norwegian Bokmål åpne (“to open”), Norwegian Nynorsk and Icelandic opna (“to open”). Related to English up. Noun from Middle English open (“an aperture or opening”), from the verb. In the sports sense, however, a shortening of “open competition”.
To make or become accessible or clear for passage by moving from a shut position.
Turn the doorknob to open the door.
The door opened all by itself.
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I made a speaking trumpet of my hands and commenced to whoop “Ahoy!” and “Hello!” at the top of my lungs. […] The Colonel woke up, and, after asking what in brimstone was the matter, opened his mouth and roared “Hi!” and “Hello!” like the bull of Bashan.1913, Joseph C[rosby] Lincoln, chapter VII, in Mr. Pratt’s Patients, New York, N.Y.; London: D[aniel] Appleton and Company, →OCLC:
‘No. I only opened the door a foot and put my head in. The street lamps shine into that room. I could see him. He was all right. Sleeping like a great grampus. Poor, poor chap.’1963, Margery Allingham, chapter 20, in The China Governess: A Mystery, London: Chatto & Windus, →OCLC:
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To make or become clear by removal of objects and obstructions, so as to allow passage, access, or visibility.
The icebreaker opened the channel.
The ice melted away and the channel opened.
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He opened a path through the undergrowth.
After we left the forest, the country opened into a wide, flat plain.
I stumbled along through the young pines and huckleberry bushes. Pretty soon I struck into a sort of path that, I cal'lated, might lead to the road I was hunting for. It twisted and turned, and, the first thing I knew, made a sudden bend around a bunch of bayberry scrub and opened out into a big clear space like a lawn.1913, Joseph C[rosby] Lincoln, chapter I, in Mr. Pratt’s Patients, New York, N.Y.; London: D[aniel] Appleton and Company, →OCLC:
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To unseal or uncover, or become unsealed or uncovered.
You can open your eyes now!
Her eyes opened wide.
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He had kept on recording everything then, when he had been sure he was going to die, and he went on recording everything now, when he was suddenly consumed with hate for the boy in his arms and overwhelmed by a desire to put something—his motorcycle key would do nicely — into the interfering little prayboy’s throat and open him like a can of beer.1996, Stephen King, Desperation:
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To spread; to expand into a wider or looser position.
to open a closed fist
to open matted cotton by separating the fibres
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to open a map, book, scroll, padlock
The flower opened in the sunlight.
Her arms opened in welcome.
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To make (a bed) ready for a patient by folding back the bedcovers.
Follow agency policy, or open the bed by folding the top linens back.2013, Susan C. deWit, Patricia A. Williams, Fundamental Concepts and Skills for Nursing, page 318:
› To make or become available for use or interaction.
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To make or become operative or available.
He opened a secret bank account in Switzerland.
We're opening the phone lines in ten minutes.
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Phone lines will open in ten minutes.
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To make or become accessible to customers, clients or visitors.
I will open the shop an hour early tomorrow.
The summer fete was opened by the mayor.
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The shop opens at 9:00.
The fete opened an hour late because of bad weather.
Suiping was opened as a main station in 1912 when Rev. H. M. Nesse arrived to take charge of the mission work.1934, White Unto Harvest in China: A Survey of the Lutheran United Mission, the China Mission of the N.L.C.A., 1890-1934, →OCLC, page 76:
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To make or become receptive or susceptible (to something).
Reading this book will open you to new ideas.
This policy will open the government to criticism.
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As he grew older, he opened to new ways of doing things.
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Computing, Engineering, Mathematics, Natural sciences, Physical sciences, Sciences To connect to a resource (a file, document, etc.) for viewing or editing.
I can't open the file because someone else is editing it.
Please open the lights, the (electric) fan, the TV.
› To start or begin.
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To start (an event or activity) as the first performer or actor.
The show was opened by a terrible Elvis impersonator.
Our band opened, and they came on second.
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Vermont will open elk hunting season next week.
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With 'for' To precede another as a performer at a concert or show.
Our band opened for Nirvana.
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Of an event, activity etc., to start or get underway.
The meeting opened with a statement from the chairman.
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To bring up, broach.
I don't want to open that subject.
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To enter upon, begin.
to open a discussion
to open fire upon an enemy
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to open trade, or correspondence
to open a case in court, or a meeting
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Computing, Engineering, Mathematics, Natural sciences, Physical sciences, Sciences To start running (a program or application, especially one with a screen-based interface).
Click this icon to open Microsoft Word.
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Ball games, Cricket, Games, Hobbies, Lifestyle, Sports To begin a side's innings as one of the first two batsmen.
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Card games, Poker To bet before any other player has in a particular betting round in a game of poker.
After the first two players fold, Julie opens for $5.
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To make an open relationship or marriage, i.e., with possible additional relationships.
He assured me, unequivocally, that he was, and that he rather enjoyed the side benefits of my trysts: I was happier and living more honestly, as well as off his back about many of the issues that had been troublesome for me before we opened our relationship.2009, Jenny Block, “You Can’t Run Out of Love”, in Open: Love, Sex, and Life in an Open Marriage, 2nd edition, Berkeley, Calif.: Seal Press, →ISBN, page 172:
I wouldn’t do it unless there is a reason for it, I wouldn’t open a marriage just for fun. I think it’s too dangerous. I know I’m a monogamous type of person—I like just one person at a time; actually sleeping with more than one person in separate relationships is too confusing.2018, Rhea Orion, quoting Annika, “Case Excerpt: Annika”, in A Therapist’s Guide to Consensual Nonmonogamy: Polyamory, Swinging, and Open Marriage, New York, N.Y.; Abingdon, Oxfordshire: Routledge, →ISBN, part II (Issues and Interventions), chapter 9 (Sex and Consensual Nonmonogamy):
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Social situations involved in opening relationships are uncertain, rather than risky, environments. Although some people might say, “Absolutely not,” it may be difficult to predict the likelihood people will respond favorably to the prospect, in part because a wide range of unknown or unknowable factors may drive their willingness.2023, James K. Beggan, “How Do We Make Decisions?”, in The Decisions to Open a Relationship: To Three or Not to Three, Lanham, Md.: Lexington Books, →ISBN, page 90:
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Obsolete To disclose; to reveal; to interpret; to explain.
The king opened himself to some of his council, that he was sorry for the earl's death.1622, Francis Bacon, The History of the Reign of King Henry the Seventh:
Unto thee have I opened my cause.1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Jeremiah 20:12:
Adjective from Middle English open, from Old English open (“open”), from Proto-West Germanic *opan, from Proto-Germanic *upanaz (“open”), from Proto-Indo-European *upo (“up from under, over”). Cognates * Scots apen (“open”) * Saterland Frisian eepen (“open”) * West Frisian iepen (“open”) * Cimbrian offe (“open”) * Dutch open (“open”) * German offen (“open”) * Vilamovian ufa, uffa (“open”) * Yiddish אָפֿן (ofn, “open”) * Danish åben (“open”) * Icelandic opinn (“open”) * Norwegian Bokmål åpen (“open”) * Norwegian Nynorsk open (“open”) * Swedish öppen (“open”) Compare also Latin supinus (“on one's back, supine”), Albanian hap (“to open”). Related to up. Verb from Middle English openen, from Old English openian (“to open”), from Proto-West Germanic *opanōn, from Proto-Germanic *upanōną (“to raise; lift; open”), from Proto-Germanic *upanaz (“open”, adjective). Cognate with Saterland Frisian eepenje (“to open”), West Frisian iepenje (“to open”), Dutch openen (“to open”), German öffnen (“to open”), Danish åbne (“to open”), Swedish öppna (“to open”), Norwegian Bokmål åpne (“to open”), Norwegian Nynorsk and Icelandic opna (“to open”). Related to English up. Noun from Middle English open (“an aperture or opening”), from the verb. In the sports sense, however, a shortening of “open competition”.
1
In the definite Open or unobstructed space; an exposed location.
I can't believe you left the lawnmower out in the open when you knew it was going to rain this afternoon!
Wary of hunters, the fleeing deer kept well out of the open, dodging instead from thicket to thicket.
2
In the definite Public knowledge or scrutiny; full view.
We have got to bring this company's corrupt business practices into the open.