Pronunciation: (ō'pun),[key] —adj. 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.
3. having no means of closing or barring: an open portico. 4. having the interior immediately accessible, as a box with the lid raised or a drawer that is pulled out.
5. relatively free of obstructions to sight, movement, or internal arrangement: an open floor plan. 6. constructed so as to be without cover or enclosure on the top or on some or all sides: an open boat. 7. having relatively large or numerous spaces, voids, or intervals: an open architectural screen; open ranks of soldiers. 8. perforated or porous: an open texture. 9. relatively unoccupied by buildings, fences, trees, etc.: open country. 10. not covered or closed; with certain parts apart: open eyes; open mouth. 11. without a covering, esp. a protective covering; unprotected; unenclosed; exposed: an open wound; open electrical wires. 12. extended or unfolded: an open newspaper. 13. without restrictions as to who may participate: an open competition; an open session. 14. accessible or available to follow: the only course still open to us. 15. not taken or filled; not preempted; available; vacant: Which job is open? 16. ready for or carrying on normal trade or business: The new store is now open. The office is open on Saturdays. 17. not engaged or committed: Have you any open time on Monday? 18. accessible, as to appeals, ideas, or offers: to be open to suggestion. 19. exposed to general view or knowledge; existing, carried on, etc., without concealment: open disregard of the rules. 20. acting publicly or without concealment, as a person.
21. unreserved, candid, or frank, as persons or their speech, aspect, etc.: an open manner. 22. generous, liberal, or bounteous: to give with an open hand. 23. liable or subject: open to question; open to retaliation. 24. undecided; unsettled: several open questions. 25. without effective or enforced legal, commercial, or moral regulations: an open town. 26. unguarded by an opponent: an open wide receiver. 27. noting the part of the sea beyond headlands or enclosing areas of land: to sail on the open seas. 28. free of ice, as a body of water or a seaport.
29. free of navigational hazards: an open coast. 30. (of a seaport) available for foreign trade; not closed by government regulations or by considerations of health.
31. (of a microphone) in operation; live.
32. (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. Cf. close (def. 56).
33. not yet balanced or adjusted, as an account.
34. not constipated, as the bowels.
35. Phonet. a. (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. b. (of a syllable) ending with a vowel.
c. (of a consonant) continuant (opposed to stopped).
36. Ling.(of a class of items) readily admitting new members, as the class of nouns, verbs, or adjectives (opposed to closed).
37. Print. a. (of type) in outline form.
b. widely spaced or leaded, as printed matter.
38. Music. a. (of an organ pipe) not closed at the far end.
b. (of a string) not stopped by a finger.
c. (of a note) produced by such a pipe or string or, on a wind instrument, without the aid of a slide, key, etc.
39. Math. a. (of an interval) containing neither endpoint.
b. (of a set) consisting of points having neighborhoods wholly contained in the set, as the set of points within a circle.
c. (of a map from one topological space to another) having the property that the image of an open set is an open set.
40. free from frost; mild or moderate: an open winter. 41. Animal Husb.(of a female animal) not pregnant.
42. Textiles.(of a fabric or weave) so loosely woven that spaces are visible between warp and filling yarns.
—v.t. 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.
3. to render the interior of (a box, drawer, etc.) readily accessible.
4. to clear (a passage, channel, etc.) of obstructions.
5. to clear (areas or passages in the body).
6. to give access to; make accessible or available, as for use: to open a port for trade. 7. to establish for business purposes or for public use: to open an office. 8. to set in action, begin, start, or commence (sometimes fol. by up): to open a campaign. 9. to uncover, lay bare, or expose to view.
10. to expand, unfold, or spread out: to open a map. 11. to make less compact, less closely spaced, or the like: to open ranks. 12. to disclose, reveal, or divulge.
13. to render accessible to knowledge, enlightenment, sympathy, etc.: to open one's mind. 14. to cut, blast, or break into: to open a safe with nitro. 15. to make or produce (an opening) by cutting or breaking, or by pushing aside or removing obstructions: to open a way through a crowd. 16. to make an incision or opening in: to open a boil. 17. Law. a. to recall or revoke (a judgment, decree, etc.) for the purpose of allowing further contest or delay.
b. to make the first statement of (a case) to the court or jury.
18. Cards.to begin a hand by making (the first bid), placing (the first bet), or playing (a given card or suit) as the lead.
19. Naut.to sail (a course) so that the apparent location of a distant fixed object changes with relation to a nearer fixed object (sometimes fol. by out).
—v.i. 1. to become open, as a door, building, box, or enclosure.
2. to afford access: a door that opens into a garden. 3. to have an opening, passage, or outlet: The room opens into a corridor. 4. (of a building, theater, etc.) to open its doors to the public: The museum opens at one o'clock. 5. to begin a session or term, as a school.
6. to begin a season, series of performances, or tour, as a theatrical company: The play will open in Boston. 7. to begin, start, or commence an activity: The game opened with the national anthem. 8. 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. 9. to become disclosed or revealed.
10. to come into view; become more visible or plain.
11. to become receptive to knowledge, sympathy, etc., as the mind.
12. to disclose or reveal one's knowledge, thoughts, feelings, etc.
13. to unfold or expand, as a blossom, so as to reveal the interior.
14. to spread out or expand, as the hand or a fan.
15. to spread apart or separate, as pages of a book, newspaper, etc.: Open to page 32. 16. to spread or come apart; burst: The wound opened. 17. to become less compact, less closely spaced, or the like: The ranks began to open. 18. Cards.to make the first bet, bid, or lead in beginning a hand.
19. Hunting.(of hounds) to begin to bark, as on the scent of game.
20. open up, a. to become or make open.
b. to expand, esp. before the eye: A breathtaking panorama opened up as we reached the top of the hill. c. to achieve the initial development of: to open up a business office; to open up trade with China. d. Slang.to increase speed or the speed of (a vehicle).
—n. 1. an open or clear space.
2. the open air.
3. the open water, as of the sea.
4. an opening or aperture.
5. an opening or opportunity.
6. a contest or tournament in which both amateurs and professionals may compete, esp. in golf.
7. the open, a. the unenclosed or unobstructed country.
b. the outdoors: Vacations in the open are fine for the entire family. c. the condition of being unconcealed, recognized, or publicly known: The scandal is now out in the open.