Rontgen ray
Ray Ray, n. [OF. rai, F. rais, fr. L. radius a beam or ray, staff, rod, spoke of a wheel. Cf. {Radius}.] 1. One of a number of lines or parts diverging from a common point or center, like the radii of a circle; as, a star of six rays. [1913 Webster]

2. (Bot.) A radiating part of a flower or plant; the marginal florets of a compound flower, as an aster or a sunflower; one of the pedicels of an umbel or other circular flower cluster; radius. See {Radius}. [1913 Webster]

3. (Zo["o]l.) (a) One of the radiating spines, or cartilages, supporting the fins of fishes. (b) One of the spheromeres of a radiate, especially one of the arms of a starfish or an ophiuran. [1913 Webster]

4. (Physics) (a) A line of light or heat proceeding from a radiant or reflecting point; a single element of light or heat propagated continuously; as, a solar ray; a polarized ray. (b) One of the component elements of the total radiation from a body; any definite or limited portion of the spectrum; as, the red ray; the violet ray. See Illust. under {Light}. [1913 Webster]

5. Sight; perception; vision; -- from an old theory of vision, that sight was something which proceeded from the eye to the object seen. [1913 Webster]

All eyes direct their rays On him, and crowds turn coxcombs as they gaze. --Pope. [1913 Webster]

6. (Geom.) One of a system of diverging lines passing through a point, and regarded as extending indefinitely in both directions. See {Half-ray}. [1913 Webster]

{Bundle of rays}. (Geom.) See {Pencil of rays}, below.

{Extraordinary ray} (Opt.), that one of two parts of a ray divided by double refraction which does not follow the ordinary law of refraction.

{Ordinary ray} (Opt.) that one of the two parts of a ray divided by double refraction which follows the usual or ordinary law of refraction.

{Pencil of rays} (Geom.), a definite system of rays.

{Ray flower}, or {Ray floret} (Bot.), one of the marginal flowers of the capitulum in such composite plants as the aster, goldenrod, daisy, and sunflower. They have an elongated, strap-shaped corolla, while the corollas of the disk flowers are tubular and five-lobed.

{Ray point} (Geom.), the common point of a pencil of rays.

{R["o]ntgen ray} (r[~e]nt"g[e^]n r[=a]`) (Phys.), a kind of ray generated in a very highly exhausted vacuum tube by the electrical discharge; now more commonly called {X-ray}. It is composed of electromagnetic radiation of wavelength shorter than that of ultraviolet light, and is capable of passing through many bodies opaque to light, and producing photographic and fluorescent effects by which means pictures showing the internal structure of opaque objects are made, called radiographs, sciagraphs, X-ray photographs, radiograms, or X-rays. So called from the discoverer, W. C. R["o]ntgen.

{X ray}, the R["o]ntgen ray; -- so called by its discoverer because of its enigmatical character, x being an algebraic symbol for an unknown quantity. [1913 Webster +PJC]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Rontgen ray — R[ o]ntgen ray, Roentgen ray Roentgen ray [see {R[ o]ntgen}.] (Physics) An {X ray}; originally, the term was applied to any of the rays produced when cathode rays strike upon surface of a solid (as the wall of the vacuum tube), but now it refers… …   The Collaborative International Dictionary of English

  • röntgen ray — röntgen ray, = X ray. (Cf. ↑X ray) …   Useful english dictionary

  • Rontgen ray — Roentgen ray Roentgen ray the Anglicised spelling of {R[ o]ntgen ray}. Same as {X ray}. [PJC] …   The Collaborative International Dictionary of English

  • Röntgen-Gymnasium Würzburg — Schulform Gymnasium Gründung 1910 (als Oberrealschule) Ort Würzburg Land Bayern Staat Deutschland Koordinaten …   Deutsch Wikipedia

  • Röntgen, Wilhelm Conrad — or Wilhelm Conrad Roentgen born March 27, 1845, Lennep, Prussia died Feb. 10, 1923, Munich, Ger. German physicist. He taught at the Universities of Giessen (1879–88), Würzburg (1888–1900), and Berlin (1900–20). In 1895 he discovered rays that did …   Universalium

  • Röntgen-Absorptionsspektroskopie — Röntgenabsorptionsspektroskopie (zu Englisch: X ray Absorption Spectroscopy: XAS) ist ein Oberbegriff für mehrere röntgenspektroskopische Messverfahren: Röntgen Nahkanten Absorptions Spektroskopie, englisch x ray absorption near edge structure… …   Deutsch Wikipedia

  • Röntgen-Photoelektronenspektroskopie — Typisches PES System mit Halbkugelanalysator, Röntgenröhren und diversen Präparationsmethoden Die Photoelektronenspektroskopie (PES) oder Photoemissionsspektroskopie (kurz Photoemission) beruht auf dem äußeren Photoeffekt, bei dem durch… …   Deutsch Wikipedia

  • Röntgen — For other uses of röntgen or roentgen , see RoentgenThe röntgen or roentgen (symbol R) is a unit of measurement for ionizing radiation (such as X ray and gamma rays), and is named after the German physicist Wilhelm Röntgen. 1 R is the amount of… …   Wikipedia

  • Röntgen-Nahkanten-Absorptions-Spektroskopie — Die Röntgen Nahkanten Absorptions Spektroskopie, englisch Near Edge X ray Absorption Fine Structure spectroscopy, kurz NEXAFS oder X ray absorption near edge structure (XANES), ist ein Spektroskopie Verfahren zur Untersuchung von… …   Deutsch Wikipedia

  • Röntgen-Beugung — Strukturbestimmung mit Röntgenbeugung Röntgenbeugung (international X Ray Diffraction, XRD), oder auch Röntgenstreuung (synonyme Begriffe), ist die Beugung von Röntgenstrahlung an geordneten Strukturen wie Kristallen oder Quasikristallen.… …   Deutsch Wikipedia

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