<B>photochemical, </B>adjective, noun.<DL COMPACT><DD><I>adj. </I> of or having to do with the chemical action of light. <BR> <I>Ex. Night sky glow not caused by moonlight and starlight is due to photochemical reactions in the upper air (Science News Letter).</I> <DD><I>noun </I> a chemical produced by the action of light on a substance. adv. <B>photochemically.</B> </DL>
<A NAME="photochemicalglass">
<B>photochemical glass,</B><DL COMPACT><DD> a composition of photosensitive glass which can be cut by acid. </DL>
<A NAME="photochemist">
<B>photochemist, </B>noun.<DL COMPACT><DD> a person who studies or is skilled in photochemistry. </DL>
<A NAME="photochemistry">
<B>photochemistry, </B>noun.<DL COMPACT><DD> the branch of chemistry dealing with the chemical action of light, as in photography. </DL>
<A NAME="photochrome">
<B>photochrome, </B>noun.<DL COMPACT><DD> a photograph in colors; a colored picture produced by color photography. </DL>
<A NAME="photochromic">
<B>photochromic, </B>adjective.<DL COMPACT><DD><B> 1. </B>changing colors when exposed to light. <BR> <I>Ex. A reversible photochromic glass--one that darkens on exposure to light and clears again when the light fades--has been invented (Scientific American).</I> <DD><B> 2. </B>having to do with photochromes. </DL>
<A NAME="photochromism">
<B>photochromism, </B>noun.<DL COMPACT><DD> the quality or property of being photochromic. </DL>
<A NAME="photochromy">
<B>photochromy, </B>noun.<DL COMPACT><DD> (Obsolete.) color photography. </DL>
<A NAME="photochronograph">
<B>photochronograph, </B>noun.<DL COMPACT><DD><B> 1. </B>a device for photographing a moving object at regular, brief intervals. <DD><B> 2. </B>a photograph so taken. <DD><B> 3. </B>an instrument for photographing the transit of a star. <DD><B> 4. </B>a device for measuring and recording small time intervals. </DL>
<B>photocoagulation, </B>noun.<DL COMPACT><DD> coagulation induced by laser beams. <BR> <I>Ex. In ... photocoagulation, for example, one of the problems has been that the red light of the ruby is not well absorbed by the red color of hemoglobin, thus limiting its effectiveness in treating blood vessel diseases of the retina (Scientific American).</I> </DL>
<A NAME="photocoagulator">
<B>photocoagulator, </B>noun.<DL COMPACT><DD> a laser device used in photocoagulation. </DL>
<A NAME="photocompose">
<B>photocompose, </B>transitive verb, <B>-posed,</B> <B>-posing.</B><DL COMPACT><DD> to prepare (printing plates) by photocomposition; compose on a photocomposing machine. noun <B>photocomposer.</B> </DL>
<A NAME="photocomposing">
<B>photocomposing, </B>adjective.<DL COMPACT><DD> of or having to do with photocomposition. </DL>
<A NAME="photocomposition">
<B>photocomposition, </B>noun.<DL COMPACT><DD> a method of typesetting in which images of type are made on film or photosensitive paper and then transferred to metal printing plates. </DL>
<A NAME="photoconductance">
<B>photoconductance, </B>noun.<DL COMPACT><DD> (Electricity.) conductance varying with illumination. </DL>
<A NAME="photoconducting">
<B>photoconducting, </B>adjective.<DL COMPACT><DD> conducting electricity only upon exposure to light. <BR> <I>Ex. photoconducting materials.</I> </DL>
<A NAME="photoconduction">
<B>photoconduction</B> or <B>photo-conduction, </B>noun.<DL COMPACT><DD> the ability of an electrical conductor to conduct electricity upon exposure to light. </DL>
<A NAME="photoconductive">
<B>photoconductive, </B>adjective.<DL COMPACT><DD> of or having to do with photoconduction; photoconducting. <BR> <I>Ex. photoconductive detectors.</I> </DL>
<A NAME="photoconductivity">
<B>photoconductivity, </B>noun.<DL COMPACT><DD> (Electricity.) conductivity varying with illumination. </DL>
<A NAME="photoconductor">
<B>photoconductor, </B>noun.<DL COMPACT><DD> a conductor whose ability to conduct electricity improves notably upon exposure to light. </DL>
<A NAME="photocopier">
<B>photocopier, </B>noun.<DL COMPACT><DD> a device or machine that produces photocopies. </DL>
<A NAME="photocopy">
<B>photocopy, </B>noun, pl. <B>-copies,</B> verb, <B>-copied,</B> <B>-copying.</B><DL COMPACT><DD><I>noun </I> a photographic copy of a document or print, reproduced by a device which photographs and automatically develops images of the original. <DD><I>v.t. </I> to produce a photocopy of. </DL>
<A NAME="photocurrent">
<B>photocurrent, </B>noun.<DL COMPACT><DD> (Physics.) the electric current produced by the movement of a stream of electrons given off by certain substances, usually in a photoelectric cell, when exposed to light or certain other radiations. </DL>
<B>photodegradable, </B>adjective.<DL COMPACT><DD> that can be decomposed by the action of light, especially sunlight; photolytic. <BR> <I>Ex. Scientists also created photodegradable plastics that break down through long exposure to sunlight (Biesenburger, Kelleher, and Xanthos).</I> </DL>
<A NAME="photodetector">
<B>photodetector, </B>noun.<DL COMPACT><DD> a semiconductor device that detects radiant energy, especially infrared radiation, by photoconductive or photovoltaic action, used especially in electronic equipment to detect changes in temperature, in solar telescopes. </DL>
<A NAME="photodisintegration">
<B>photodisintegration, </B>noun.<DL COMPACT><DD> (Physics.) the breaking down of the nucleus of an atom caused by bombardment with high-energy gamma rays. </DL>
<A NAME="photodissociation">
<B>photodissociation, </B>noun.<DL COMPACT><DD> dissociation of a chemical compound by the absorption of radiant energy, such as light and ultraviolet rays. </DL>
<A NAME="photodrama">
<B>photodrama, </B>noun.<DL COMPACT><DD> a motion picture; photoplay. </DL>
<A NAME="photodramatic">
<B>photodramatic, </B>adjective.<DL COMPACT><DD><B> 1. </B>of or having to do with a photodrama. <DD><B> 2. </B>like a photodrama. </DL>
<A NAME="photodramatist">
<B>photodramatist, </B>noun.<DL COMPACT><DD> a writer of photodramas. </DL>
<A NAME="photoduplication">
<B>photoduplication, </B>noun.<DL COMPACT><DD> the act or process of making photocopies. </DL>
<A NAME="photodynamic">
<B>photodynamic, </B>adjective.<DL COMPACT><DD> having to do with the energy of light. </DL>
<A NAME="photodynamics">
<B>photodynamics, </B>noun.<DL COMPACT><DD> the science dealing with the energy of light, especially in relation to growth or movement in plants. </DL>
<A NAME="photoelastic">
<B>photoelastic, </B>adjective.<DL COMPACT><DD> of or having to do with photoelasticity. </DL>
<A NAME="photoelasticity">
<B>photoelasticity, </B>noun.<DL COMPACT><DD> (Physics.) optical changes in a transparent dielectric, such as glass, due to compression or other stresses. </DL>
<A NAME="photoelectric">
<B>photoelectric, </B>adjective.<DL COMPACT><DD><B> 1. </B>having to do with the electricity or the electrical effects produced by the action of light or other radiation. <BR> <I>Ex. The photoelectric measurement of starlight has become ... a major instrument for studying the universe (New Astronomy).</I> <DD><B> 2. </B>of or having to do with an apparatus for taking photographs by electric light. adv. <B>photoelectrically.</B> </DL>
<B>photoelectric cell,</B><DL COMPACT><DD><B> 1. </B>any cell or vacuum tube, used for the detection and measurement of light, that varies the flow of electric current according to the amount of light falling upon its sensitive element; electric eye; photocell. Variations or interruptions of the light can set off alarms. Solar cells are photoelectric cells. <BR> <I>Ex. This light falls on a photoelectric cell which produces an electric current corresponding to the intensity of the light (John Pierce).</I> <DD><B> 2. </B><B>=phototube.</B> </DL>
<A NAME="photoelectriceffect">
<B>photoelectric effect,</B><DL COMPACT><DD> the transfer of the kinetic energy of a photon in light or gamma radiation to an electron of a metal it strikes, causing the emission or escape of the electron. </DL>
<A NAME="photoelectricexposuremeter">
<B>photoelectric exposure meter,</B><DL COMPACT><DD> (Photography.) a type of exposure meter in which the light on a subject is measured by a photoelectric cell. </DL>
<A NAME="photoelectricity">
<B>photoelectricity, </B>noun.<DL COMPACT><DD><B> 1. </B>electricity produced or affected by light. <DD><B> 2. </B>the science dealing with electricity or electrical effects produced by light. </DL>
<A NAME="photoelectron">
<B>photoelectron, </B>noun.<DL COMPACT><DD> an electron emitted from a surface exposed to light. </DL>
<A NAME="photoelectronic">
<B>photoelectronic, </B>adjective.<DL COMPACT><DD> of or having to do with the relationships between electricity and light. </DL>
<A NAME="photoelectronics">
<B>photoelectronics, </B>noun.<DL COMPACT><DD> the study and application of the effects of electricity and light upon each other. </DL>
<A NAME="photoelectrotype">
<B>photoelectrotype, </B>noun.<DL COMPACT><DD> an electrotype made by photography. </DL>
<A NAME="photoemission">
<B>photoemission, </B>noun.<DL COMPACT><DD> the emission of electrons from a metal subjected to the action of light or other suitable radiation. </DL>
<A NAME="photoemissive">
<B>photoemissive, </B>adjective.<DL COMPACT><DD> giving out, or capable of giving out, electrons when subjected to the action of light or other suitable radiation. <BR> <I>Ex. photoemissive metals.</I> </DL>
<A NAME="photoemitter">
<B>photoemitter, </B>noun.<DL COMPACT><DD> a photoemissive substance. </DL>
