<B>photomagnetic, </B>adjective.<DL COMPACT><DD> designating certain rays of the spectrum having, or supposed to have, a magnetic influence. </DL>
<A NAME="photomagnetism">
<B>photomagnetism, </B>noun.<DL COMPACT><DD> the science dealing with the relation of magnetism to light. </DL>
<A NAME="photomap">
<B>photomap, </B>noun, verb, <B>-mapped,</B> <B>-mapping.</B><DL COMPACT><DD><I>noun </I> <B>1. </B>a map made from an aerial photograph or photographs, now usually one in which a number of photographs made from a given altitude are matched and given, by means of an overlay, such conventional characteristics of a map as a grid and lines of contour. <BR> <I>Ex. a photomap of Tokyo.</I> <DD><B> 2. </B>a star map prepared by means of a phototelescope. <BR> <I>Ex. When the atlas is completed ... it will include 1,758 ... "photomaps" (London Times).</I> <DD><I>v.t. </I> to prepare a photomap or photomaps of. <BR> <I>Ex. to photomap the skies by using a telescopic camera. The project ... may lead to photomapping of nearly every square inch of land in the Western hemisphere (Science News Letter).</I> </DL>
<A NAME="photomechanical">
<B>photomechanical, </B>adjective.<DL COMPACT><DD> having to do with or designating any method of printing in which the plate or other printing surface is prepared by means of a photographic and a mechanical process, as photoengraving, photogravure, or photo-offset. adv. <B>photomechanically.</B> </DL>
<A NAME="photometer">
<B>photometer, </B>noun.<DL COMPACT><DD> any one of various instruments for measuring light, such as the intensity of light, light distribution, illumination, or luminous flux. <BR> <I>Ex. The photometer is used to measure, simultaneously, the luminosities and diameters of galaxies lying beyond those in our own neighborhood of the universe (Science News).</I> </DL>
<A NAME="photometric">
<B>photometric, </B>adjective.<DL COMPACT><DD> having to do with photometry or a photometer. adv. <B>photometrically.</B> </DL>
<B>photometrist, </B>noun.<DL COMPACT><DD> a person who studies or is skilled in photometry. </DL>
<A NAME="photometry">
<B>photometry, </B>noun.<DL COMPACT><DD><B> 1. </B>the branch of physics dealing with measurements of the intensity of light, light distribution, illumination, and luminous flux. <DD><B> 2. </B>the measurement of light, especially with the aid of the photometer. </DL>
<A NAME="photomicrograph">
<B>photomicrograph, </B>noun.<DL COMPACT><DD> an enlarged photograph of a microscopic object, taken through a microscope; microphotograph. </DL>
<A NAME="photomicrographic">
<B>photomicrographic, </B>adjective.<DL COMPACT><DD><B> 1. </B>of, having to do with, or used in photomicrography. <BR> <I>Ex. photomicrographic apparatus.</I> <DD><B> 2. </B>obtained or made by photomicrography. </DL>
<A NAME="photomicrography">
<B>photomicrography, </B>noun.<DL COMPACT><DD> the art of obtaining photographs of microscopic objects on a magnified scale by replacing the eyepiece of a microscope with a camera. </DL>
<A NAME="photomicroscope">
<B>photomicroscope, </B>noun.<DL COMPACT><DD> an apparatus consisting of a microscope, a camera, and a light source, all mounted on a stable base, and used to photograph microscopic objects. </DL>
<A NAME="photomontage">
<B>photomontage, </B>noun.<DL COMPACT><DD><B> 1. </B>the process of combining several photographs, or parts of them, into a single picture. <DD><B> 2. </B>the resulting picture. </DL>
<A NAME="photomosaic">
<B>photomosaic, </B>noun.<DL COMPACT><DD> a group of aerial photographs put together to form a continuous photograph of an area. </DL>
<A NAME="photomultiplier">
<B>photomultiplier, </B>noun. or <B>photomultiplier tube,</B><DL COMPACT><DD> a vacuum tube having a series of supplementary electrodes between the photocathode and the anode. When light strikes the photoemissive cathode a cascade of electrons is emitted and amplified at each supplementary electrode. </DL>
<A NAME="photomural">
<B>photomural, </B>noun.<DL COMPACT><DD> a mural consisting of a greatly enlarged photograph or group of matched photographs. </DL>
<A NAME="photon">
<B>photon, </B>noun.<DL COMPACT><DD> a unit particle of light, an element of radiant energy, according to the quantum theory; a light quantum. It has a momentum equal to its energy divided by the velocity of light, and moves as a unit with the velocity of light. It is considered to be one of the elementary particles. <BR> <I>Ex. [Einstein] said that light, in spite of its wave nature, must be composed of energy particles, or photons (Harvey E. White). When you see different colors your eyes are being hit by streams of photons which differ in their rates of vibration (Ralph E. Lapp).</I> </DL>
<A NAME="photonasty">
<B>photonasty, </B>noun.<DL COMPACT><DD> (Biology.) response to diffuse light or to variations in the intensity of light, as in the growth of a plant organ. </DL>
<A NAME="photonegative">
<B>photonegative, </B>adjective.<DL COMPACT><DD> showing avoidance of light; photophobic. <BR> <I>Ex. Normally the beetles are photonegative, tending to stay in the dark half of the chamber (New Scientist).</I> </DL>
<A NAME="photonovel">
<B>photonovel, </B>noun.<DL COMPACT><DD> a novel depicted in photographs and legends, with dialogue usually enclosed in a circled or boxed space in the style of a comic strip. </DL>
<A NAME="photonuclear">
<B>photonuclear, </B>adjective.<DL COMPACT><DD> of or having to do with the action or effect of photons upon atomic nuclei. </DL>
<A NAME="photooffset">
<B>photo-offset, </B>noun, verb, <B>-set,</B> <B>-setting.</B><DL COMPACT><DD><I>noun </I> a process of printing in which a page of type, a picture, or other matter is photographed and the image then transferred to a specially sensitized lithographic plate and printed by offset; offset lithography. <DD><I>v.t. </I> to print or reproduce by photo-offset. </DL>
<B>photo opportunity,</B><DL COMPACT><DD> (U.S. and Canadian.) a session in which publicity pictures are taken. <BR> <I>Ex. Campaign Canny ground into a week of staged photo opportunities and scripted shouting matches (Maclean's).</I> </DL>
<A NAME="photooxidation">
<B>photooxidation, </B>noun.<DL COMPACT><DD> oxidation induced by the chemical action of light. <BR> <I>Ex. Cellulose is a prey to all four of the major museum enemies: photooxidation, humidity change, air pollution, and biological attack (New Scientist).</I> </DL>
<A NAME="photoperiod">
<B>photoperiod, </B>noun.<DL COMPACT><DD> the length of time during which a plant or animal is exposed to light each day, considered especially with reference to the effect of the light on growth and development. </DL>
<A NAME="photoperiodic">
<B>photoperiodic, </B>adjective.<DL COMPACT><DD> of or having to do with a photoperiod or photoperiodism. <BR> <I>Ex. photoperiodic behavior.</I> adv. <B>photoperiodically.</B> </DL>
<A NAME="photoperiodical">
<B>photoperiodical, </B>adjective. <B>=photoperiodic.</B> <I>Ex. There is some kind of photoperiodical response in every higher plant (Science News Letter).</I> </DL>
<A NAME="photoperiodism">
<B>photoperiodism, </B>noun.<DL COMPACT><DD> (Physiology.) the response of a plant or animal to the length of its daily exposure to light, especially as shown by changes in vital processes. <BR> <I>Ex. Photoperiodism ... is largely responsible for the separation of many wild flowers into spring, summer, and fall blooming classes (Science News Letter).</I> </DL>
<A NAME="photophilous">
<B>photophilous, </B>adjective.<DL COMPACT><DD> (of an organism) flourishing in strong light, especially sunlight; light-loving. </DL>
<A NAME="photophily">
<B>photophily, </B>noun.<DL COMPACT><DD> the quality or condition of living or flourishing in light. </DL>
<A NAME="photophobia">
<B>photophobia, </B>noun.<DL COMPACT><DD><B> 1. </B>an abnormal dread of, or shrinking from, light. <DD><B> 2. </B>extreme sensitivity to light. <BR> <I>Ex. Paralysis of these muscles [of the iris] puts the iris at rest and decreases the pain and photophobia (Sidney Lerman).</I> </DL>
<A NAME="photophobic">
<B>photophobic, </B>adjective.<DL COMPACT><DD> showing photophobia; shrinking from light; photonegative. <BR> <I>Ex. The mole is photophobic (James Neylon).</I> </DL>
<A NAME="photophone">
<B>photophone, </B>noun.<DL COMPACT><DD> a telephone in which sound vibrations are conveyed by means of a beam of reflected light. </DL>
<A NAME="photophore">
<B>photophore, </B>noun.<DL COMPACT><DD> a luminous, cup-shaped organ on the bellies of certain deep-sea crustaceans and fishes. </DL>
<A NAME="photophoresis">
<B>photophoresis, </B>noun.<DL COMPACT><DD> the unidirectional movement of small particles, suspended in gas or falling in a vacuum, produced by a beam of light. </DL>
<A NAME="photophosphorylation">
<B>photophosphorylation, </B>noun.<DL COMPACT><DD> phosphorylation induced by the presence of radiant energy in the form of visible or nonvisible light. <BR> <I>Ex. Cyclic photophosphorylation ... provides a mechanism for the utilization of light energy without the consumption of water (Science).</I> </DL>
<A NAME="photopia">
<B>photopia, </B>noun.<DL COMPACT><DD> the ability to see in light, especially sunlight, of a sufficient intensity to permit color differentiation. </DL>
<A NAME="photopic">
<B>photopic, </B>adjective.<DL COMPACT><DD> able to see in light of a sufficient intensity to permit color differentiation. </DL>
<A NAME="photopigment">
<B>photopigment, </B>noun.<DL COMPACT><DD> a pigment whose characteristics are changed by the action of light. <BR> <I>Ex. The photochemist cannot study the photopigments of a single receptor in living animals and the finest microelectrode is gross in size when compared with the diameter of some of the processes which we assume to carry electric potentials in the nerve net (Science Journal).</I> </DL>
<A NAME="photoplay">
<B>photoplay, </B>noun.<DL COMPACT><DD> a motion-picture story or scenario. <BR> <I>Ex. It is a good deal better than either the photoplay or the novel which were its cause (Atlantic).</I> </DL>
<A NAME="photopolarimeter">
<B>photopolarimeter, </B>noun.<DL COMPACT><DD> an instrument combining telescopic, photographic, and polarimetric apparatus for producing detailed images of planetary features. </DL>
