[ oh-puhn ]
See synonyms for: openopenedopeningopenly on

  1. not closed or barred at the time, as a doorway by a door, a window by a sash, or a gateway by a gate: to leave the windows open at night.

  2. (of a door, gate, window sash, or the like) set so as to permit passage through the opening it can be used to close.

  1. having no means of closing or barring: an open portico.

  2. having the interior immediately accessible, as a box with the lid raised or a drawer that is pulled out.

  3. relatively free of obstructions to sight, movement, or internal arrangement: an open floor plan.

  4. constructed so as to be without cover or enclosure on the top or on some or all sides: an open boat.

  5. having relatively large or numerous spaces, voids, or intervals: an open architectural screen; open ranks of soldiers.

  6. perforated or porous: an open texture.

  7. relatively unoccupied by buildings, fences, trees, etc.: open country.

  8. not covered or closed; with certain parts apart: open eyes; open mouth.

  9. without a covering, especially a protective covering; unprotected; unenclosed; exposed: an open wound; open electrical wires.

  10. extended or unfolded: an open newspaper.

  11. without restrictions as to who may participate: an open competition; an open session.

  12. accessible or available to follow: the only course still open to us.

  13. not taken or filled; not preempted; available; vacant: Which job is open?

  14. ready for or carrying on normal trade or business: The new store is now open. The office is open on Saturdays.

  15. not engaged or committed: Have you any open time on Monday?

  16. accessible, as to appeals, ideas, or offers: to be open to suggestion.

  17. exposed to general view or knowledge; existing, carried on, etc., without concealment: open disregard of the rules.

  18. acting publicly or without concealment, as a person.

  19. unreserved, candid, or frank, as persons or their speech, aspect, etc.: an open manner.

  20. generous, liberal, or bounteous: to give with an open hand.

  21. liable or subject: open to question; open to retaliation.

  22. undecided; unsettled: several open questions.

  23. without effective or enforced legal, commercial, or moral regulations: an open town.

  24. unguarded by an opponent: an open wide receiver.

  25. noting the part of the sea beyond headlands or enclosing areas of land: to sail on the open seas.

  26. free of ice, as a body of water or a seaport.

  27. free of navigational hazards: an open coast.

  28. (of a seaport) available for foreign trade; not closed by government regulations or by considerations of health.

  29. (of a microphone) in operation; live.

  30. (of a delimiting punctuation mark) occurring at the beginning of a group of words or characters that is set off, as from surrounding text: open parenthesis; open quotes.: Compare close (def. 47).

  31. not yet balanced or adjusted, as an account.

  32. not constipated, as the bowels.

  33. Phonetics.

    • (of a vowel) articulated with a relatively large opening above the tongue or with a relatively large oral aperture, as the vowel sound of cot compared with that in caught.

    • (of a syllable) ending with a vowel.

    • (of a consonant) continuant (opposed to stop).

  34. Linguistics. (of a class of items) readily admitting new members, as the class of nouns, verbs, or adjectives (opposed to closed).

  35. Printing.

    • (of type) in outline form.

    • widely spaced or leaded, as printed matter.

  36. Music.

    • (of an organ pipe) not closed at the far end.

    • (of a string) not stopped by a finger.

    • (of a note) produced by such a pipe or string or, on a wind instrument, without the aid of a slide, key, etc.

  37. Mathematics.

    • (of an interval) containing neither endpoint.

    • (of a set) consisting of points having neighborhoods wholly contained in the set, as the set of points within a circle.

    • (of a map from one topological space to another) having the property that the image of an open set is an open set.

  38. free from frost; mild or moderate: an open winter.

  39. Animal Husbandry. (of a female animal) not pregnant.

  40. Textiles. (of a fabric or weave) so loosely woven that spaces are visible between warp and filling yarns.

verb (used with object)
  1. to move (a door, window sash, etc.) from a shut or closed position so as to admit of passage.

  2. to render (a doorway, gateway, window, etc.) unobstructed by moving a door, window sash, etc., away from it.

  1. to render the interior of (a box, drawer, etc.) readily accessible.

  2. to clear (a passage, channel, etc.) of obstructions.

  3. to clear (areas or passages in the body).

  4. to give access to; make accessible or available, as for use: to open a port for trade.

  5. to establish for business purposes or for public use: to open an office.

  6. to set in action, begin, start, or commence (sometimes followed by up): to open a campaign.

  7. to uncover, lay bare, or expose to view.

  8. to expand, unfold, or spread out: to open a map.

  9. to make less compact, less closely spaced, or the like: to open ranks.

  10. to disclose, reveal, or divulge.

  11. to render accessible to knowledge, enlightenment, sympathy, etc.: to open one's mind.

  12. to cut, blast, or break into: to open a safe with nitro.

  13. to make or produce (an opening) by cutting or breaking, or by pushing aside or removing obstructions: to open a way through a crowd.

  14. to make an incision or opening in: to open a boil.

  15. Law.

    • to recall or revoke (a judgment, decree, etc.) for the purpose of allowing further contest or delay.

    • to make the first statement of (a case) to the court or jury.

  16. Cards. to begin a hand by making (the first bid), placing (the first bet), or playing (a given card or suit) as the lead.

  17. Nautical. to sail (a course) so that the apparent location of a distant fixed object changes with relation to a nearer fixed object (sometimes followed by out).

verb (used without object)
  1. to become open, as a door, building, box, or enclosure.

  2. to afford access: a door that opens into a garden.

  1. to have an opening, passage, or outlet: The room opens into a corridor.

  2. (of a building, theater, etc.) to open its doors to the public: The museum opens at one o'clock.

  3. to begin a session or term, as a school.

  4. to begin a season, series of performances, or tour, as a theatrical company: The play will open in Boston.

  5. to begin, start, or commence an activity: The game opened with the national anthem.

  6. to part, or seem to part, so as to allow or reveal a passage: At last the cliffs opened to show us that we were heading for the sea.

  7. to become disclosed or revealed.

  8. to come into view; become more visible or plain.

  9. to become receptive to knowledge, sympathy, etc., as the mind.

  10. to disclose or reveal one's knowledge, thoughts, feelings, etc.

  11. to unfold or expand, as a blossom, so as to reveal the interior.

  12. to spread out or expand, as the hand or a fan.

  13. to spread apart or separate, as pages of a book, newspaper, etc.: Open to page 32.

  14. to spread or come apart; burst: The wound opened.

  15. to become less compact, less closely spaced, or the like: The ranks began to open.

  16. Cards. to make the first bet, bid, or lead in beginning a hand.

  17. Hunting. (of hounds) to begin to bark, as on the scent of game.

  1. an open or clear space.

  2. the open air.

  1. the open water, as of the sea.

  2. an opening or aperture.

  3. an opening or opportunity.

  4. a contest or tournament in which both amateurs and professionals may compete, especially in golf and tennis.

  5. the open,

    • the unenclosed or unobstructed country.

    • the outdoors: Vacations in the open are fine for the entire family.

    • the condition of being unconcealed, recognized, or publicly known: The scandal is now out in the open.

Verb Phrases
  1. open up,

    • to become or make open.

    • to expand, especially before the eye: A breathtaking panorama opened up as we reached the top of the hill.

    • to achieve the initial development of: to open up a business office; to open up trade with China.

    • Slang. to increase speed or the speed of (a vehicle).

Origin of open

First recorded before 900; (adjective) Middle English, Old English; cognate with Old Saxon opan (Dutch open ), Old High German offan (German offen ), Old Norse opinn, akin to up; (verb) Middle English openen, Old English openian; cognate with Old Saxon opanon (Dutch openen ), Old High German offanōn (German öffnen )

synonym study For open

21. See frank1.

Other words from open

  • o·pen·ly, adverb
  • o·pen·ness, noun
  • half-o·pened, adjective
  • pre·o·pen, verb (used with object)
  • self-o·pened, adjective
  • sem·i·o·pen, adjective
  • sem·i·o·pen·ly, adverb
  • un·o·pened, adjective

Words Nearby open Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use open in a sentence

British Dictionary definitions for open


/ (ˈəʊpən) /

  1. not closed or barred: the door is open

  2. affording free passage, access, view, etc; not blocked or obstructed: the road is open for traffic

  1. not sealed, fastened, or wrapped: an open package

  2. having the interior part accessible: an open drawer

  3. extended, expanded, or unfolded: an open newspaper; an open flower

  4. ready for business: the shops are open

  5. able to be obtained; available: the position advertised last week is no longer open

  6. unobstructed by buildings, trees, etc: open countryside

  7. free to all to join, enter, use, visit, etc: an open competition

  8. unengaged or unoccupied: the doctor has an hour open for you to call

  9. not decided or finalized: an open question

  10. ready to entertain new ideas; not biased or prejudiced: an open mind

  11. unreserved or candid: she was very open in her description

  12. liberal or generous: an open hand

  13. extended or eager to receive (esp in the phrase with open arms)

  14. exposed to view; blatant: open disregard of the law

  15. liable or susceptible: you will leave yourself open to attack if you speak

  16. (of climate or seasons) free from frost; mild

  17. free from navigational hazards, such as ice, sunken ships, etc: open water

  18. US without legal restrictions or enforceable regulations, esp in relation to gambling, vice, etc: an open town

  19. without barriers to prevent absconding: an open prison

  20. having large or numerous spacing or apertures: open ranks

  21. full of small openings or gaps; porous: an open texture

  22. printing (of type matter) generously leaded or widely spaced

  23. music

    • (of a violin or guitar string) not stopped with the finger

    • (of a pipe, such as an organ pipe) not closed at either end

    • (of a note) played on such a string or pipe

  24. commerce

    • in operation; active: an open account

    • unrestricted; unlimited: open credit; open insurance cover

  25. (of a return ticket) not specifying a date for travel

  26. sport

    • (of a goal, court, etc) unguarded or relatively unprotected: the forward missed an open goal

    • (of a stance, esp in golf) characterized by the front of the body being turned forward

  27. (of a wound) exposed to the air

  28. (esp of the large intestine) free from obstruction

  29. undefended and of no military significance: an open city

  30. phonetics

    • denoting a vowel pronounced with the lips relatively wide apart

    • denoting a syllable that does not end in a consonant, as in pa

  31. chess (of a file) having no pawns on it

  32. maths (of a set) containing points whose neighbourhood consists of other points of the same set: points inside a circle are an open set

  33. computing (of software or a computer system) designed to an internationally agreed standard in order to allow communication between computers, irrespective of size, maufacturer, etc

  1. to move or cause to move from a closed or fastened position: to open a window

  2. (when intr, foll by on or onto) to render, be, or become accessible or unobstructed: to open a road; to open a parcel; the door opens into the hall

  1. (intr) to come into or appear in view: the lake opened before us

  2. (tr) to puncture (a boil) so as to permit drainage

  3. to extend or unfold or cause to extend or unfold: to open a newspaper

  4. to disclose or uncover or be disclosed or uncovered: to open one's heart

  5. to cause (the mind) to become receptive or (of the mind) to become receptive

  6. to operate or cause to operate: to open a shop

  7. (when intr, sometimes foll by out) to make or become less compact or dense in structure: to open ranks

  8. to set or be set in action; start: to open a discussion; to open the batting

  9. (tr) to arrange for (a bank account, savings account, etc) usually by making an initial deposit

  10. to turn to a specified point in (a book, magazine, etc): open at page one

  11. law to make the opening statement in (a case before a court of law)

  12. (intr) cards to bet, bid, or lead first on a hand

  1. the open any wide or unobstructed space or expanse, esp of land or water

  1. sport a competition which anyone may enter

  2. bring into the open to make evident or public

  3. come into the open to become) evident or public

Origin of open

Old English; related to Old French open, epen, Old Saxon opan, Old High German offan

Derived forms of open

  • openable, adjective
  • openly, adverb
  • openness, noun

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

Other Idioms and Phrases with open


In addition to the idioms beginning with open

  • open and aboveboard
  • open and shut
  • open book
  • open doors
  • open fire
  • open house, keep
  • open mind
  • open one's eyes
  • open one's heart to
  • open one's mouth
  • open question
  • open season on
  • open secret
  • open the door to
  • open up
  • open with

also see:

  • keep a weather eye (open)
  • keep one's eyes open
  • lay open
  • leave open
  • leave the door open
  • not open one's mouth
  • out in the open
  • throw open
  • wide open
  • with one's eyes open
  • with open arms

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