Not permitting a radiation to pass through.
Adj. form of → opacity.
O.E. open "not closed down, raised up," also "uncovered, bare; plain, evident," related to up; from P.Gmc. *upana (cf. O.N. opinn, Swed. öppen, Dan. aaben, O.Fris. epen, O.H.G. offan "open"), from PIE *upo "up from under, over;" cf. L. sub; Gk. hypo; O.Pers. upā (prep.) "under, with;" Av. upā, upa (prep.; prevb) "toward, with, on, in;" Mod.Pers. bâ "with," from abâ; Skt. úpa (adv., prevb., prep.) "toward, with, under, on."
Bâz "open," from Mid.Pers. abâz-, apâc-, O.Pers. apa- [pref.] "away, from;" Av. apa- [pref.] "away, from," apaš [adv.] "toward the back;" cf. Skt. ápāñc "situated behind."
xuše-ye bâz (#)
Fr.: amas ouvert
A loose grouping of dozens or hundreds of young stars distributed in a region a few light-years across. Open clusters are relatively young, typically containing many hot, highly luminous stars. They are located within the disk of the Galaxy, whence their older name Galactic clusters.
Fr.: intervalle ouvert
An interval that does not include its two endpoints.
open magnetic field line
xatt-e bâz-e meydân-e meqnâtisi-ye
Fr.: ligne ouverte de champ magnétique
In the context of solar physics, a → magnetic field line when it crosses the solar surface only once, i.e., when it goes from surface to infinity. This is the case at a sufficiently large scale in → coronal holes. This is mostly not the case in → active regions.
Fr.: ensemble ouvert
A set consisting of points having neighborhoods wholly contained in the set, as the set of points within a circle.
fazâ-ye bâz (#)
Fr.: espace ouvert
A space of infinite volume without any boundary. Triangles which lie on the surface of an open space will have a sum of angles which is less than 180°. An open space has a negative → curvature. See also → open Universe, → closed space.
Fr.: système ouvert
giti-ye bâz (#)
Fr.: Univers ouvert
Fr.: FBF ouverte
The capability of being put into use, operation, or practice.
Capable of operating or of being operated.
To function or work; to make something function or work.
From L. operari "to work, labor," L. opus "a work, labor, exertion," Av. *āpah-, *apah- "to do, operate," see below, Skt. ápas- "work, action, religious act;" O.H.G. uoben "to start work, to practice, to honor;" Ger. üben "to exercise, practice;" Du. oefenen; O.E. æfnan "to perform, work, do," afol "power"); PIE base *op- "to work, perform."
Âpâridan, from âpâr-, from Av. *āp(ah)- "to do, operate," as above, + suffix -ar (as in vadar- "weapon," zafar- "jaw," baēvar- "thousand," and so on), shifted to -âr, + -idan suffix of infinitives. The Av. *āpah- "to do, operate," is extant in Mod.Pers. xub "good;" Mid.Pers. hwp, xub "good;" from Av. huuāpah- "doing good work, masterly," from huu-, hv- "good" → eu- + āpah- "work, deed," hauuapanha- "creativity;" cf. Skt. sv-ápas- "doing good work, skillful;" PIE base *op-, as above.
operating system (OS)
Fr.: système d'exploitation
1) General: An act or instance, process, or manner of functioning or operating.
Verbal noun of → operate
Pertaining to a process or series of actions for achieving a result.
Adj. of → operation.
Fr.: calcul opérationnel
A method of mathematical analysis which in many cases makes it possible to reduce the study of differential operators, pseudo-differential operators and certain types of integral operators, and the solution of equations containing them, to an examination of simpler algebraic problems. It is also known as operational analysis.
In the philosophy of science, the view that → concepts are defined in terms of measuring operations which determine their applicability. Same as operationism.
Math.: Something that acts on another function to produce another function. In linear algebra an "operator" is a linear operator. In calculus an "operator" may be a differential operator, to perform ordinary differentiation, or an integral operator, to perform ordinary integration.
A small satellite of → Uranus, the second nearest to the planet, discovered from the images taken by the Voyager 2 spacecraft in 1986. Also denoted Uranus II, it has a diameter of 32 km. Ophelia is one of the two → shepherd moons that keep the planet's Epsilon ring, the other being → Cordelia.
Ophelia is the daughter of Polonius in Shakespeare's Hamlet.