X-ray
n 1: electromagnetic radiation of short wavelength produced when
high-speed electrons strike a solid target [syn: X ray,
X-ray, X-radiation, roentgen ray]
2: a radiogram made by exposing photographic film to X rays;
used in medical diagnosis [syn: roentgenogram, X ray,
X-ray, X-ray picture, X-ray photograph]
v 1: examine by taking x-rays
2: take an x-ray of something or somebody; "The doctor x-rayed
my chest"
|
radiograph \ra"di*o*graph\ (r[=a]"d[i^]*[-o]*gr[a^]f), n.
[Radio- + -graph.]
1. An instrument for measuring and recording solar radiation.
[Webster 1913 Suppl.]
2. An image or picture produced upon a sensitive surface, as
of a photographic or fluorescent plate, by some form of
penetrating radiation other than light, as X-rays, beta
rays, etc.; esp., a picture of the internal structure of
opaque objects traversed by the rays; a skiagraph. When
the picture is produced upon photographic film by X-rays,
the picture is usually called an X-ray photo or X-ray.
When an image is produced on photographic film by a
radioactive substance in close proximity to the film, in a
manner so as to record the spatial distribution of the
radioactive substance, the resulting image is called an
autoradiograph or autoradiogram.
[Webster 1913 Suppl. +PJC]
|
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. (Zool.)
(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.
Roentgen ray, R["o]ntgen ray (r[~e]nt"g[e^]n r[=a]`)
(Phys.), a form of electromagnetic radiation generated in
a very highly exhausted vacuum tube by an electrical
discharge; now more commonly called X-ray. It is
composed of electromagnetic radiation of wavelength
shorter than that of ultraviolet light but longer than
that of gamma rays. It 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
X-rays, radiographs, sciagraphs, X-ray photographs,
radiograms. 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]
|
X ray \X ray\, X-ray \X-ray\([e^]ks"r[=a]`), n. [so called by
its discoverer because of its enigmatical character, x being
an algebraic symbol for an unknown quantity.] (Physics)
Originally, any of the rays produced when cathode rays strike
upon surface of a solid (as a copper target or the wall of
the vacuum tube); now defined as electromagnetic radiation
with a wavelength of 0.1 to 10 nanometers. X-rays are noted
for their penetration of many opaque substances, as wood and
flesh, their action on photographic plates, and their
fluorescent effects. They were called X rays by their
discoverer, W. K. R["o]ntgen, but were also referred to for
some time as Roentgen rays. The term X-ray has become the
most common designation. They also ionize gases, but cannot
be reflected, or polarized, or deflected by a magnetic field.
They are used in examining objects opaque to visible light,
as for imaging bones or other structures inside the human
body, and for detecting flaws in metal objects, such as in
welds.
[Webster 1913 Suppl. +PJC] X ray
|