Main Entry: ¹open

Pronunciation: \ˈō-pən, -p^əm\

Function: adjective

Inflected Form(s): open·er \ˈōp-nər, ˈō-pə-\; open·est \ˈōp-nəst, ˈō-pə-\

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

Date: before 12th century

1 : having no enclosing or confining barrier : accessible on all or nearly all sides <cattle grazing on an open range>
2 a (1) : being in a position or adjustment to permit passage : not shut or locked <an open door> (2) : having a barrier (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>
3 a : 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
4 a : not covered with a top, roof, or lid <an open car> <her eyes were open> b : having no protective covering <open wiring> <an open wound>
5 : not restricted to a particular group or category of participants <open to the public> <open housing>: as a : enterable by both amateur and professional contestants <an open tournament> b : enterable by a registered voter regardless of political affiliation <an open primary>
6 : fit to be traveled over : presenting no obstacle to passage or view <the open road> <open country>
7 : having the parts or surfaces laid out in an expanded position : spread out : unfolded <an open book>
8 a (1) : low 13 (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
9 a : 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 : not proprietary : available to third party developers <open source code>
10 a : characterized by ready accessibility and usually generous attitude: as (1) : generous in giving (2) : willing to hear and consider or to accept and deal with : responsive (3) : free from reserve or pretense : frank b : accessible to the influx of new factors (as foreign goods) <an open market>
11 a : having openings, interruptions, or spaces <open mesh>: as (1) : being porous and friable <open soil> (2) : sparsely distributed : scattered <open population> (3) of a compound : having components separated by a space in writing or printing (as opaque projector) b : not made up of a continuous closed circuit of channels <the insect circulatory system is open>
12 a of an organ pipe : not stopped at the top b of a string on a musical instrument : not stopped by the finger
13 : 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>
14 a (1) : characterized by lack of effective regulation of various commercial enterprises <an open town> (2) : not repressed 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>
15 : having been opened by a first ante, bet, or bid <the bidding is open>
16 of punctuation : characterized by sparing use especially of the comma
17 a : 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>
18 a : being an incomplete electrical circuit b : not allowing the flow of electricity <an open switch>
19 of a universe : having insufficient mass to halt expansion gravitationally

synonyms see frank, liable

— open adverb

— open·ly \ˈō-pən-lē\ adverb

— open·ness \-pə(n)-nəs\ noun