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/steuh ray"dee euhn/, n. Geom.
a solid angle at the center of a sphere subtending a section on the surface equal in area to the square of the radius of the sphere. Abbr.: sr

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▪ unit of measurement
unit of solid-angle measure in the International System of Units (SI), defined as the solid angle of a sphere subtended by a portion of the surface whose area is equal to the square of the sphere's radius. Since the complete surface area of a sphere is 4π times the square of its radius, the total solid angle about a point is equal to 4π steradians. Derived from the Greek for solid and the English word radian, a steradian is, in effect, a solid radian; the radian is an SI unit of plane-angle measurement defined as the angle of a circle subtended by an arc equal in length to the circle's radius.

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Universalium. 2010.

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• stéradian — [ steradjɑ̃ ] n. m. • 1923; angl. steradian (1881); du gr. stereos « solide » (cf. stéréo ) et radian ♦ Unité de mesure d angle solide (symb.sr). ● stéradian nom masculin ( …   Encyclopédie Universelle

• steradian — STERADIÁN, steradieni, s.m. Unitate de măsură pentru unghiurile corpurilor solide. [pr.: di an] – Din fr. stéradian. Trimis de claudia, 18.04.2008. Sursa: DEX 98 ﻿ steradián s. m. (sil. di an), pl. steradiéni (sil. di eni); simb. str Trimis de… …   Dicționar Român

• steradian — [stə rā′dē ən] n. [ STE(REO) + RADIAN] the basic unit of solid angular measure in the SI system, equal to the solid angle subtended at the center of a sphere by an area, on its surface, that is equal to the square of its radius: one sphere equals …   English World dictionary

• Stéradian — Le stéradian (symbole : sr) est l unité dérivée du système international pour la mesure d angles solides. Sa définition est similaire à celle du radian qui mesure les angles plans. Son nom est partiellement dérivé du grec ancien στερεός… …   Wikipédia en Français

• Steradian — The steradian (symbol: sr) is the SI unit of solid angle. It is used to describe two dimensional angular spans in three dimensional space, analogous to the way in which the radian describes angles in a plane. The name is derived from the Greek… …   Wikipedia

• Steradian — steradianas statusas T sritis Standartizacija ir metrologija apibrėžtis Erdvinio kampo išvestinio SI matavimo vieneto specialus pavadinimas. Steradianas – tai erdvinis kampas su viršūne sferos centre, išpjaunantis sferos paviršiuje figūrą,… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• steradian — steradianas statusas T sritis Standartizacija ir metrologija apibrėžtis Erdvinio kampo išvestinio SI matavimo vieneto specialus pavadinimas. Steradianas – tai erdvinis kampas su viršūne sferos centre, išpjaunantis sferos paviršiuje figūrą,… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• stéradian — steradianas statusas T sritis Standartizacija ir metrologija apibrėžtis Erdvinio kampo išvestinio SI matavimo vieneto specialus pavadinimas. Steradianas – tai erdvinis kampas su viršūne sferos centre, išpjaunantis sferos paviršiuje figūrą,… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• steradian — (sr)    the standard unit of solid angle measure in mathematics. Just as there are 2pi radians in a circle, there are 4pi steradians in a sphere. Thus one steradian equals about 0.079 577 sphere. There are 129 600/pi = 41 252.96 square degrees in …   Dictionary of units of measurement