Definition of: open

(ō′pən) adjective
1. Affording approach, view, passage, or access because of the absence or removal of barriers, restrictions, etc.; unobstructed: The new road is open for traffic; open country.
2. Public; unbounded; accessible to all: the open market; in open competition; the open sea.
3. Unconcealed; overt; not secret or hidden: open hostility.
4. Expanded; unfolded: an open flower.
5. Exposed; not enclosed or covered over; unprotected: an open car.
6. Ready for business, appointment, etc.: an open day in the schedule.
7. Not settled or decided; pending: an open account; an open question.
8. Ready and free for engagement, employment, etc.; available: The job is still open.
9. Ready to consider proof or argument; unbiased; receptive: often with to: an open mind; open to conviction.
10. Generous; liberal: He gives with an open hand.
11. Phonet. a Pronounced with a wide opening above the tongue; low: said of vowels, as the a in father: opposed to close. b Ending in a vowel or diphthong: said of a syllable.
12. Frank; ingenuous; not deceptive: open and aboveboard.
13. Eager or willing to receive: with open arms.
14. In hunting or fishing, without prohibition: open season.
15. Liable to attack, robbery, temptation, etc.
16. Having openings, holes, or perforations, as woven goods or needlework; porous.
17. Mild; free from fog, mist, or ice: an open winter; open weather; open water in northern seas.
18. Printing a Widely spaced, as a line on a page. b Widely leaded or containing many breaks; fat: said of composed or printed matter.
19. Music Not stopped by the finger, as a string, or having the top uncovered, as an organ pipe; also, produced by an open string or pipe: said of a note, tone, etc.
20. Unrestricted by union regulations in the employment of labor: an open shop.
21. U.S. Colloq. Not under control in the sale of intoxicants, gambling, or vice: an open town.
22. Out of doors.
23. U.S. Of or designating a policy of admitting students for matriculation to a college or university without regard to their academic preparedness, thus providing an opportunity for members of disadvantaged groups to obtain university degrees: open admissions.
24. In the elementary grades, of or characterized by an educational environment designed to encourage self-motivated learning by giving children freedom to move from one small group to another within and sometimes beyond the limits of the classroom: open classrooms. See synonyms under BLUFF², CANDID, EVIDENT, MANIFEST, NOTORIOUS, OVERT.
—v.t.
1. To Set open or ajar, as a door; unclose; unfasten.
2. To make passable; free from obstacles.
3. To make or force (a hole, passage, etc.).
4. To remove the covering, lid, etc., of: to open a package.
5. To expand, as for viewing; unroll; unfold, as a map.
6. To make an opening or openings into: to open an abscess.
7. To make or declare ready for commerce, use, etc.: to open a store.
8. To make or declare public or free of access, as a park; make available for settlement.
9. To make less compact; expand: to open ranks.
10. To make more receptive to ideas or sentiments; enlighten: to open the mind.
11. To bare the secrets of; divulge; reveal: to open one's heart.
12. To begin; commence, as negotiations.
13. Law To undo or recall (a judgment or order) so as to permit its validity to be questioned.
—v.i.
14. To become open.
15. To come apart or break open; rupture: The wound opened again.
16. To come into view; spread out; unroll.
17. To afford access or view: The door opened on a courtyard.
18. To become receptive or enlightened.
19. To begin; be started: The season opened with a ball.
20. In the theater, to begin a season or tour.
—noun Any wide space not enclosed, obstructed, or covered, as by woods, rocks, etc.; open land or water: usually with the definite article: in the open. [OE. Akin to UP.]
—o′pen·ly adverb
—o′pen·ness noun