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`
`McGRAW-HILL
`DICTIONARY OF
`SCIENTIFIC AND
`TECHNICAL
`·.TERMS
`
`-:, I '
`
`) ..
`
`McGraw· Hill
`. Chicago San Francisco
`New York
`Lisbon London Madrid Mexico City
`Milan New Delhi San Juan Seoul Singapore Sydney Toronto
`
`

`

`On the cover: Representation of a fullerene molecule with a noble gas atorn trapped
`inside. At the Permian· Triassic sedimentary boundary the noble gases helium and argon
`have been found trapped inside fullerenes. They exhibit isotope ratios quite similar to
`those found in meterorites, suggesting that a fireball meteorite or asteroid exploded
`when it hit the Earth, causing major changes in the environment. {Image copyright ©
`Dr. Luann Becker. Reproduced with permission.)
`
`Over the six editions of the Dictionary, material ha$ been drawn(l'Dm the folltiwing references: G. M. Garrity
`eta!., Taxonomic Outline of the Procaryote$'; Release 2; Springer-Verlag, January 2002; D. W. Linzey, Vertebrate
`Biology, McGraw-Hill, 2001; J. A. Pechenik, Biology of the Invertebrates, 4th ed., McGraw-Hill, 2000; U.S.
`Air Force Glossary of Standardized Terms, AF Manual 11-1, vol. 1, 1972; F. Casey, ed., Compilation of Terms
`in Information Sciences Technology, Federal Council for Science and Technology, 1970; Communications(cid:173)
`Electronics Terminology, AF Manual 11-1, vol. 3, 1970; P. W. Thrush, comp. and ed., A Dictionary of Mining,
`Mineral, and Related Terms, Bureau of Mines, 1968; A DOD Glossary of Mapping, Charting and Geodetic
`Terms, Department of Defense, 1967; J. M. Gilliland, Solar-Terrestrial Physics: A Glossary of Terms and
`Abbreviations, Royal Aircraft Establishment Technical Report 67158, 1967; W. H. Allen, ed., Dictionary of
`Technical Terms for Aermpace Use, National Aeronauticsand Space Administration, 1965; Glossary of Stinfo
`Terminology, Office of Aerospace Research, U.S. Air Force, 1963; Naval Dictionary of Electronic, Technical,
`and Imperative Terms, Bureau of Naval Personnel, !962; R. E. Huschke; Glossary of Meteorology, American
`Meteorological Society, 1959; ADP Glossary, Department of the Navy, NAVSO P-3097; Glossary of Air Traffic
`Control Terms, Federal Aviation Agency; A Glossary of Range Termin()!og}~ White Sands Missile Range, New
`Mexico, National Bureau of Standards, AD 467C:424; Nuclear TrmiS: A, Glossary, 2d ed., Atomic Energy
`Commission.
`
`McGRAW-HILL DICTIONARY Of SCIENTIFIC AND TECHNICAL TERMS,
`Sixth Edition
`Copyright © 2003, 1994, 1989, 1984, 1978, 1976, 1974 by The McGraw-Hill Companies, Inc. All rights
`reserved. Printed in the United States of America. Except as permitted under the United States Copyright Act
`of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored
`in a database or retrieval system, without the prior written permission of the publisher.
`
`1234567890
`
`DOW/DOW
`
`08765432
`
`ISBN 0-07-042313-X
`
`Library of Congress Cataloging-in-Publication Data
`
`McGraw-Hill dictionary of scientific and technical terms--6th ed.
`p.
`em.
`ISBN 0-07-042313-X (alk. paper)
`1. Science--Dictionaries. 2. Technology--Dictionaries.
`and technical terms.
`
`I. Title: Dictionary of scientific
`
`Q123.M15
`503-dc21
`
`2002
`
`2002026436
`
`

`

`value.
`ci'fECH) To remove something, especially gases
`[~·~om an enclosure, -su9h as. from, the envelope of
`tube, or from a well. ; Als.o known as, exhaust.
`...
`.
`}
`.
`[Jl'lvzoo) The ensign flit1S; afamily ofhymenop(cid:173)
`iJJ the superfamily Proctotrupoidea. L ,ev·a'ui·
`.
`.
`.
`NERA-L] Al3(PO.)(OHk6Hj0 A_<;olorless to
`.
`.[M~neralconsi~ting of a hydrated.basic aluminum
`• pccurs in massive form and as stalactites. _: (''<)~':
`
`. Water present iii: <;apillari~s or
`water
`[MATER]
`·· .. forces in cement that has set;. measured .as the
`that can be removed by drying under specified
`'""'"r•,•hC>I 'w,6d·;;>r }
`[ifoOD ENG) A product made by~removing
`· whole milk thflt the final product contains
`fat or 25.9%, total milk solids. { ilvap·a,rad·
`
`Conversi~~ of a liquid to the va.por state
`heat. { i,vap·d'ra·sh<Jn )
`,;,a1oaclt'V•See .evaporative powet.
`·{ i,vap•<J'.ra·.
`
`current
`•[OCEANOGR] An · ocean
`accumulation of water through precipitation
`one point, and loss by evaporation at.another
`· ,k<J·ranU
`{ i,vap•<J'ra·sh')n ,gaj')
`a!mo,Weter.
`· [QHEM ENG] The Joss qf a stqmd voli1;t.i.l.y
`or mixture by ·evaporat.ion;. controlled by
`. and. the presence or.,aqscnce of vapor-(cid:173)
`[i,vap:<J'r~·sh;;.n ,los }
`[EN.Q] A type of atmometer consi>sting qf
`measurement of the evaporation of water
`\ i,vap·;;.'ra·sh;;~n ,pan}
`See evaporative power ... { i,vap·;;.'.ra·sh<Jn
`
`[ENG] A tank used to measure theevapo"
`c.ontrolled conditions. {i,vap·<l'ra·
`
`[MECH ENG] An apparatus in which
`tJ.~bes that are cooled by the·evapora"
`over the qutside of the tubes ... ( i'vap'
`)
`sys~em [MECJ-I ENG] A motor vehiclg
`escape of gasoline vapors from. the fuel
`the atmosphere ,whilesl)e engine ,is :.not
`,,v;m·:,.n,n·•· k<Jn.'trol ,sis·tgm }
`. 1. Lowering the \em perature of
`[ENG]
`,. , ·' . .,., ... _by utilizing the latent heat of vaporization
`liquid. 2. Cooling airby evappr~ting,water
`( i'vap·;;~,rad·iv 'kiil·,
`vaporization cooling.
`
`[PHYSIO]. Thecompositeproc:
`is cooled by evaporation of
`ofhe~t loss serves as a physii
`-,-.,-.. , .. ,, .... ~body temperature. {i'vap:;;.,rad·
`
`·~
`.
`of
`An , or
`[MECH
`liquid is changed to,,the
`stat} bof many devices in
`l'la~er Y th~ addition of heat, for example, distiller, still;
`punf~er, or refrigeration ·system .~lement where
`
`.
`
`evaporatipn procee,ds at .low pressure and consequent,low:tem(cid:173)
`perature.
`(. i'vap·<J·,rad·ar}
`evaporimeter See atmometer. { i,vap·<l'riirt·gd·Gr}
`evaporite
`[GEOL] Deposits of mjnetal salts from sea water
`or salt lakes due. to evaporation of the water. { i'vap·<J,l'lt)
`evaporite pond
`(IND ENG} Any containment area for brines
`or solution-mined effluents constructed to.permits0lar evapora;
`tion ,and harvesting of dewatered evaporite• concentrates.
`(.i'vap·;;.,rit' ,pand }
`evapotranspiration
`[HY,D} Discharge· of water frorri the
`earth's surface to tlie atmosphere by evaporation from lakes,
`streams, and soil, surfaces. and by transpiration from plants.
`Also ktiown as fly-off; total evaporation;'water loss.
`.{ i,vap·
`o,tranz·p;;~'ra·sh<Jn}
`evapotranspirometer
`[ENG] An instrument which ·.meas(cid:173)
`ures the rate of evapotranspiration;-consists of a vegetation soil.
`tank so designed tbat all water added to the tank and all water
`left after· evapotranspiration can be measured.
`( i,vap·o,tranz.·
`pa'ram·;;.ch:>r }
`Evase stack
`[crv ENG]
`In tunnel engineering, ari exhaust
`stack for air-having a cross section that incre·aHes in the direction'
`of airflow. at a rate to regain pressure.
`r:a,va:za ,stak.J
`[ASTROPHYS] A perturbation of the moon in its
`evection
`orbit ·due to ihe attraction of the sun.
`( e'vekish<Jh J
`E vector
`[ELECTROMAG] Vector representing the electric
`field of an ele'ctromagnetic w'ave. { 'e , vek·wr }
`even-even nucleus [Nuc PHYS} A nucleus which has un
`even number of neutrons and an even number of protons.
`{ :e·
`v<Jn :e·v<Jn ,nii·kle·as }
`'
`,
`even function
`[MATH] A function with the property that
`f(?:) = f( .::.x)'for each number X.
`. ( 'e·v;;in ,f;;~Uk•shgn·}
`even harmonic
`[PHYS] A hllrmoniC that is an even multiple
`{ :e·y;;.n h~r,m~n·ik. )
`of the fundamental t'requency.
`[ ORD] Firing of a gun as a signal for the lm;:(cid:173)
`evening gun
`ering of the 11ag at retreat; ihe gun is fired. after ~he sounding
`ofthe last note"of the•bugle call at retreaf. Also known as
`retreat gun·.'" l :e¥·'nio 'g;;>I)}'
`·
`·
`..
`evening star
`'A misnqmer for U planet that can
`[ASTRON}
`be seen witho\It a telescope when it sets aft~ the sun. { :ev·
`nil} !stiir J
`·
`,
`·
`·.
`evening twilijjht, i [ASTRciN} The period of time bi::tween sun(cid:173)
`?et and dmknb.s. { ;ev·niu 'twi,ln J
`eve" keel
`[NAY AR<;H] Floating Je~~l. without inclination.
`{ )e·vd!i.' 'kel}
`,
`·
`.
`even number
`J\n integyr which is a multiple of 2.
`[MATH]
`{ 'e·v(m ,nilip·b;;>r)
`even-odd riucl~US . [NUC PHYS J A nuci~us which has an even
`number of ptotoris and an odd number of ne,Utrons.
`(\e·v<Jn
`lad .'nii·kle·ils 'j
`. ..
`·
`. . . ..
`[COMPUT sq] A parity chec\< in which
`eve.n pari~y check
`the nl.lmb'er of" O's or l 's in each word is expected to be even.
`{ :e·v;;.n 'par·;;>d·e ,chek }
`·
`even· permutation
`[MATH] A p.ermutati911. which, may be
`represented as a result of an even number .of transpositions.
`( :e·vGn p<Jr·my<J'ta·sh<Jn )
`, ·
`even pitch
`[DES ENG). The ,pitch of a screw in which the
`number.of threl)dS. per iiich is a multiple (Or submultiple) of
`tile threads per)nch of the lead screW of the lathe on which
`the screw is cut.
`( ie·v<Jn 'pich }
`.
`[ cOMI?UT sci l The moment of time at y;hlcl) a speci(cid:173)
`event
`fied change, of state occurs; usually.ljlarks the completion of an
`[ <;JEOH An incident of
`asynchronous input/output operation.
`probable tectonic significance, but whose full implications are.
`J;.. sp~cified <,~ccornp\ishrrient in a pro(cid:173)
`unknown.
`[IND E':!G]
`gram at a particular time; appears as. a nqde in a graphic repre(cid:173)
`sentation of an endeavor with a specific. objective (project),
`[PHYS1 A point in space-time.· [STAT] A mathematical
`model of the result of a conceptual experiment; this model L~
`a measurable subset of a probability space. { i'vent}
`event-driven monitor
`[coMPUT scrJ A computer program
`!hat-measures the pprformaQ.ce of a computer system bY count(cid:173)
`(.i'vent ldriv·<Jn 'man·
`ing the tasks.performed by the system.
`Gd·;;>rJ
`event horizon
`[RELAT] The boundary of ~regjon of space·
`time ~rol)l which it \s.not.possibl~ to escape to in~injty.,$ymbol-
`ized :J>+.
`(i'venth;;.,rrz·;;.n)
`·
`Eventogn;:~thi . [vnRT zoo J The equivalent nanw for Cypriui(cid:173)
`formes.
`( ,e,ven'tag·n<J,thr}
`
`_.
`
`t:ventognatm r
`
`EVAPORATOR
`
`vapor
`
`t
`
`feed liquor
`
`Long-tube vertical evaporator.
`
`

`

`Also known as instrumental conditionin~; rein(cid:173)
`
`conditioning. { 'ap·;:,·r;mt k;:,n'dish·;:,·nil] r
`
`[COMPUT SCI] The phase of computer opera7
`an instruction is being carried out.
`[ELECI Total
`from application of energizing current to a relay
`··time the contacts have opened or closed. { 'tip·
`}.
`angle
`
`[ELECTR] Electrical angle of the input sig(cid:173)
`portion of a cycle) during which plate cmrent
`a vacuum tube amplifier.
`['ap·;:,,rild·iiJ ,aJ]·g;:,l}
`characteristic' curve
`In hypothesis test(cid:173)
`[STAr]
`of the probability of accepting the hypothesis against
`of nature. Abbreviated OC curve. { 'ap:;:~,rad·
`·tik 'k;:,rv}
`·
`·
`[COMPUT SCI] Computer time lost because
`or inefficiency of operating personnel or users of
`excluding time lost because of defects in programs.
`{ 'lip·;:~,rad·iiJ di,la )
`handle
`[ORD] Handle or bar. with which the
`lever of a gun is operated to open and close the
`{ 'ap·;:~,rad·iiJ ,han·d;:~l }
`instructions
`[coMPUT scr] A detailed descrip(cid:173)
`actions that must be carried out by a computer
`a program or group of interrelated programs,
`in the documentation of a program supplied
`·M•mnlmler or systems analyst, along with the source
`tlow charts.
`{ 'ap·;:~,rad·iiJ in,str;:,k·sh;:,nz )
`[ORD} Lever device on a gun with which
`is opened and closed.
`( 'ap·;:~,rad· il]' ,lev·;:,r ]
`ln the graphical solution of equi(cid:173)
`[ CHEM ENG]
`(such as distillation absorption extraction),
`liquid-vapor relationship of a key component, in
`{ 'ap·;:,,rad·iu ,llu}
`a true equilibrium relationship.
`point
`[ELECTR] Point on. a family of characteristic
`a vacuum tube or transistor where the coordinates of
`the instantaneous values of the ele~trode
`for the operating conditions under study
`{. 'ap·;:,,rad·iiJ ,p<;iint }
`,
`position
`[coMMUN] Terminal of a communicit(cid:173)
`channel which is. attended by an operator; usually the
`refers to. a single operator, such as a radio operator's
`or a telephone operator's position; however, certain
`inay require more than 'one operating position.
`p;:,,zish·;:,n]
`[ELECTIWMAG] Power that is actually sup(cid:173)
`radio transmitter antenna. { -'ap·;:,,rad·iiJ ,pau·;:,r]
`pressure . [ENG] The system pressure at which a
`operating.
`( 'ap·;:~,racl·iiJ ,presh·;:,r )
`[ELECTR] The frequency range ov6r which
`"· ''v'"'o"u'" transducer is operable.
`[NAV] The maximum
`which reliable s<;:rvice is provided by an aiel to
`.
`,
`{ 'ap·a,rad·iiJ ,ranj }
`Iii tirier~11iron ratio
`[ coMPUT sci} The time during which com·
`operat.es and gives reliable results divided by
`time scheduled for computer operation. { ~ap·;:,,racl·
`J
`.
`'
`•
`slide
`)ORD] Mechanism in a Browning machine
`that permits openipg the breech for loading, unloading,
`and clearjng out stoppages, and closing the breech for firing.
`( 'iip·;:,,rad·io ,slTd)
`•
`Operating stress
`[MEet!] The stress to. which a structm'al
`unit is subjected in service. { 'iip·;:,}ad·irJ ,stres }
`Operating sy~em [coM PUT sci) A set of programs and rou(cid:173)
`tines which guides a computer or network in the performance
`of its tasks, assists the programs (and programmers) with certain
`supporting functions, and increas~s the usefulness of the com:
`puter or network hardware. { 'ap·a,rad·io ,sis·t;:>m }
`0Perating system supervisor
`[COMPUT sci] The control
`program of a set of programs which guide a compliter in the,
`Performance of its tasks and which assist the progra1n with
`{ 'iip·;:~,rad·iiJ
`,sis,iam ··so·
`certain supporting functions.
`P<lr,vrz.~r ]
`·
`0Perating water level
`[MECH ew;J The water level In a
`boiler drum which is normally maintained above the lowest
`safe level. { 'ap·.;:~,racl·iu 'w6d·;:,r ,Jev·gl }
`0Peration
`[CoMPUT scr] 1. A process or proce,clure that
`obtains a unique result from any permissible combination of
`0Perancls. 2. The sequence of. actions resulting :from the exe(cid:173)
`[IND E~IG] A job,
`cution of one digital computer instruction.
`
`operation process chart
`
`1: 1479
`
`1.1
`
`( ,iip·;:,'rii·sh;:,n·
`
`usually performed in one location, and consisting of one or
`[MAI'H] An operation of a group G on
`more work elements.
`a setS is a mapping which associates to each ordered pair (g,s),
`where g is in G and s is in S, another element in S, denoted
`gs, such that, for any g,h in G and s inS, (gh)s = g(hs), an4
`es = s, where e is the identity element of G.
`( ,ap·;:,'ra ·sh;:,n ]
`operational · ! ENG J Of equipment such as aircraft or vehicles,
`being in such a state of repair as to be immediately usable.
`{ ,ap·;:,'ra·sh;:,n ·;:,I }
`operational advantage
`an
`air Operations,
`In
`[NAV]
`improvement which. benefits the users of an instrument proce(cid:173)
`dure, such as the ability to· use lower minimums. { ,ap·;:,'ra·
`sh;:,n·;:,l ;:~d'van·tij }
`·
`operational amplifier
`[ELECTR] An amplifier having high
`direct-current stability and high immunity to oscillation, gener(cid:173)
`ally .1.1chieved by using a large m,nount of negative feedback;
`used to perform analog-computer fimctions. such as summing
`{ ,ap·;:,'ra·sh;:,n·;:,l 'am·pl;:~,fi·;ir]
`and integrating.
`operational analysis :See operational calculus. {',iip·;:,'ra·
`sh;:,n·;:,l ;J'rial·;:>·s;:,s}
`operational calculus
`[MATH] A technique by which prob(cid:173)
`lems in analysis, in particular differential equations, are transo
`formed into algebraic problems, usually. the problem of solving
`a polynomial equation. Also known as operational analysis.
`{ ,iip·;:,'ra·sh;:,n·;:,l 'kal·ky;:~·l;:,.s}
`operational g,ame See management game.
`;:~l'gam l
`operational label
`[ coMPtrr sCI] A combinatiqn of letters
`and digits at the beginning of the tape which uniquely identify
`the tape ryquired by the system. { ,ap·;:,'ra·sh;:,n·;:,l 'la·b;:~l }
`operational malntllnance
`[ENG] The clea!Jing, servicing,
`preservation, lubrication, inspection,. and adjustment of equip:
`ment; it includes that minor replacement of parts not" requiring
`high technical skill, internal alignment, or special locative train(cid:173)
`ing. { ,iip·;:,'ra·sh;:,n-;:,1 'mant·,;:,n·;:,ns }
`operational standby program
`[coMPUT sci] The program
`operating in the standby computer when in the dup)ex )I!Ode
`of opeimion. { ,iip·;:,'ra·sh;:,n·;:,l 'stancl,br ;pro,gram}
`operational unit
`[GEOL]' An arbitrary stratigraphic unit that
`is clistinguishecll:)y objective criteria for some practical purpose. ,
`~]so known as parastratigraphic unit: { ,ap·;:,'ra·siJ;:,n·;:,l
`'yii·n;:,t}
`operational weather limits
`[METEOROL] The limiting val(cid:173)
`ues of ceiling, visibility, and wind, or runway visual' range,'
`established as safety minima for aircraft hindings ariel takeoffs.
`{ ,iip·;:,'ra·sh;:,n·;:,l 'wefu·;:,r ,lim·;:,ts ]
`operation analysis
`[IND ENG] An analysis of all procedures
`concerned with the design or improvement of production, the
`purpose of the operation, inspection standards, materials used
`and the manner of handling them, the setup, tool eqliipment,
`and working conditiOJLS and methods. { ,ap·;:,'ra·sh;:,n ;:~'nal·
`;)·S;:>S}
`.
`.. ,
`I IND ENG] A form that lists .all the
`operation analysis chart
`essential factors influencing the effectiveness of an operation.
`{ ,iip·;:,'ra·sh;:,n ;:,'nal·;:,·sos ,chart}
`operation breakdown See job breakdown.
`'brak,diuln }
`operation code
`[ COMPUT scr] A field or portion of a digital
`computer instruction that indicates which action is to be per(cid:173)
`formed by the computer. Also known .as command code,
`{ ,ap·;:,'ra·sh;:,n ,kiicl }
`..
`operation cycle
`[coMPl.IT sci] The portion of a memory
`~ycle require<) to perform an operation; division and m~ltiplica­
`tion. usually require !)lore than one memory cycle to be 'com-
`pleted. { ,ap·;:,'ra·sll;:,n ,si:k;:,] )
`·
`operation decoder
`[COMPUT sc1] A device (hat examines
`the operation contained in an instruction of a computer program
`and sends signals to .the circuits required to carry out the opera(cid:173)
`tion: { ,ap·;:,'rli·shim de'kocJ·;:,r }
`[ COMPtrr SCI] . ' 1. Number designating the
`operati6n number
`position 'of an operation,. or its equivalent subroutine, in the
`s.eqtience of operations composing a routine. 2. Number iden(cid:173)
`( ,ap:
`tifying each step in a program stated in symbolic code.
`;:,'ra·sh;:,n ,n;:~m·bor}
`.
`.
`·
`operation part [cOMPUT SCI] Tliat portion of a digital com(cid:173)
`puter instruction which is reserved for the operation· cod~;>.
`{ ,ap·;:,'ra·sh;:,n ,part }
`operation process chart. [IND ENG] A graphic ~;epresenta:
`· iion that gives an overall yiew of an entire process, including
`
`[. ,ap·;:,'ra·sh;:,n
`
`