Mlllillllw-Illll
`illlillllfllllll Ill
`3lI|[Nl|l|lI ANII
` lllillllllllll
`l[|lMS
`
`inn Etlitiun
`
`Sybil P. Parker
`Editor in Chief
`
`Auckland
`Montreal
`
`New York
`Caracas
`Bogotzi
`New Delhi
`
`McGraw-Hill, Inc.
`San Francisco
`Washington. D.C.
`Lisbon
`London
`Madrid
`San Juan
`Singapore
`Sydney
`
`Milan
`Mexico City
`Tokyo
`Toronto
`
`HP 1009
`Page 1 of 4
`
`

`
`On the cover: Photomicrograph of crystals of vitamin B1.
`(Dennis Kunkel, University of Hawaii )
`
`Included in this Dictionary are definitions which have been published previously in the following works: P. B.
`Jordain, Condensed Computer Encyclopedia, Copyright © 1969 by McGraw-Hill, Inc. All rights reserved. I.
`Markus, Electronics and Nucleonics Dictionary, 4th ed., Copyright © 1960, 1966, 1978 by McGraw-Hill, Inc.
`All rights reserved. I. Quick, Artists’ and Illustrators’ Encyclopedia, Copyright © 1969 by McGraw—Hil1, Inc. All
`rights reserved. Blakiston's Gould Medical Dictionary, 3d ed., Copyright © 1956, 1972 by MCGraw»Hill, Inc. All
`rights reserved. T. Baumeister and L. S. Marks, eds., Standard Handbook for Mechanical Engineers, 7th ed.,
`Copyright © 1958, 1967 by McGraw-Hi11,Inc. All rights reserved.
`
`In addition, material has been drawn from the following references: R. E. Huschke, Glossary of Meteorology,
`American Meteorological Society. 1959: US. Air Force Glossary of Standardized Terms, AF Manual 1 1~1. vol.
`1, 1972; Communicalions-Electronics Terminology, AF Manual 11-], vol. 3, 1970; W. H. Allen, ed., Dictionary
`of Technical Terms for Aerospace Use, 1st ed., National Aeronautics and Space Administration. 1965; J. M.
`Gilliland. Solar-Terrestrial Physirs: A Glossary of Terms and Abbreviations, Royal Aircraft Establishment Tech-
`nical Repott 67158, 1967; Glossary ofAir Trajffic Control Terms, Federal Aviation Agency; A Glossary ofRange
`Terminology. White Sands Missile Range, New Mexico. National Bureau of Standards, AD 467-424; A DOD
`Glossary ofMapping, Charting and Geodetic Terms, 1st ed., Department of Defense, 1967; P. W. Thrush, comp.
`and ed., A Dictionary ofMining, Mineral, and Related Terms. Bureau of Mines. 1968; Nuclear Terms.‘ A Glossary,
`2d ed., Atomic Energy Commission; F. Casey, ed., Compilation of Terms in Information Sciences Technology,
`Federal Council for Science and Technology, 1970; Glossary ofStinfo Terminology, Office of Aerospace Research,
`U.S. Air Force. 1963: Naval Dictionary ofElectronic. Technical. and Imperative Terms. Bureau of Naval Person-
`nel. 1962; ADP Glossary, Department of the Navy, NAVSO P—3097.
`
`MCGRAW-HILL DICTIONARY OF SCIENTIFIC AND TECHNICAL TERMS,
`Fifth Edition
`Copyright © 1994, 1989, 1984, 1978, 1976, 1974 by McGraw—Hi1l,1nc. All rights reserved. Printed in the United
`States of America. Except as peimitted 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
`
`99876543
`
`ISBN 0—07—O42333~4
`
`Library of Congress Cataloging-in-Publication Data
`
`McGraw»1-{ill dictionary of scientific and technical terms /
`Sybil P. Parker, editor in chief..—5th ed.
`p.
`cm.
`ISBN 0-07-042333-4
`1. Science~Dictionaries.
`1. Parker. Sybil P.
`Q123.M34
`1993
`503—dc20
`
`2. Technology——Dictionaries.
`
`93-34772
`CIP
`
`INTERNATIONAL EDITION
`
`Copyright © 1994. Exclusive rights by McGraw—Hil1, Inc. for manufacture and export. This book cannot be re-
`exported from the country to which it is consigned by McGraw-I-Iill. The International Edition is not available in
`North America.
`
`When ordering this title, use ISBN 0A07—1 13584-7,
`
`HP 1009
`Page 2 of 4
`
`

`
`1104
`
`Lambert-Beer law
`
`laminated contact
`
`I
`
`‘lam-
`
`conformal chart or plotting sheet; approximates a great-circle
`bearing.
`[ ‘lam-bort ,ber-in I
`Lambert-Beer law See Bouguer-Lambert-Beer law.
`bort 'bir ,lo I
`[MAP] A chart on the Lambert
`Lambert conformal chart
`conformal projection.
`I ‘lam-bart kan'fo'rmol ,chart I
`Lambert conformal proiectlon [MAP] A confonnal conic
`projection with two standard parallels, or a conformal conic map
`projection in which the surface of a sphere or spheroid, such as
`the earth, is conceived as developed on a cone which intersects
`the sphere or spheroid at two standard parallels; the cone is then
`spread out to form a plane which is the map.
`[
`'lam‘bart konjfor
`mol pr9‘jek-shon I
`[NAV] Course as measured on a Lambert
`Lambert course
`conformal chart or plotting sheet.
`I ‘lam-bort ,kors I
`Lambert’s law [OPTICS]
`1. The law that the illumination of a
`surface by a light ray varies as the cosine of the angle of inci-
`dence between the normal to the surface and the incident ray.
`2. The law that the luminous intensity in a given direction ra-
`diated or reflected by a perfectly diffusing plane surface varies
`as the cosine of the angle between that direction and the normal
`to the surface. 3. See Bouguer—Lambert law.
`I
`'lam’b9rts ,lo I
`Lambert surface [THERMO] An ideal. perfectly diffusing sur-
`face for which the intensity of reflected radiation is independent
`of direction.
`I ‘lam-bort ,s9rf9s I
`lambing storm [METEOROLI A slight fall of snow in the spring
`in England. Also known as lamb-blasts; lamb—showers: lamb—
`storm.
`I ‘lam-in ,storm I
`Lamb shift
`[ATOM rrrvs] A small shift in the energy levels of
`a hydrogen atom, and ofhydrogenlike ions, from those predicted
`by the Dirac electron theory. in accord with principles of quan-
`tum electrodyriamics.
`I ‘lam [shift I
`Lamb-shift source INUCLEOI A device for producing abeam
`of polarized ions from one—electron atoms in their 25 excited
`state: the 2s and 2p levels, initially separated by the Lamb shift,
`are mixed by magnetic and electric fields, and selected nuclear
`magnetic substrates are then depopulated, leaving the remaining
`atoms in a state with large nuclear polarization.
`I ‘lam ,shift
`,sors I
`I ‘lam ,shau~orz I
`lamb-showers See lambing storm.
`'lam,storm I
`lamb-storm See lambing storm.
`I
`lamb's wool
`[VERT zoo] The first fleece taken from a sheep
`up to 7 months old. having natural tapered fiber tip and spinning
`qualities superior to those of wool taken from previously shom
`sheep.
`{ ‘lamz will I
`IELECTROMAGI Elec-
`Lamb wave IACOUSI See plate wave.
`tromagnetic wave propagated over the surface of a solid whose
`thickness is comparable to the wavelength of the wave.
`I ‘lam
`,w2'tv I
`[TEXT] A fabric, usually of silk, rayon, or polyester.
`Iamé
`ornamented with flat metal threads.
`I la'm2‘t I
`Lamé constants
`[MECH] Two constants which relate stress
`to strain in an isotropic, elastic material.
`I la‘ma ,kan-stans I
`Lamé functions [MATH] Functions that arise when Laplace’s
`equation is separated in ellipsoidal coordinates.
`I
`la‘m2‘1 ,f9rJk-
`shanz I
`[civ ENG] A thin
`[ANAT] A thin scale or plate.
`lamella
`member made of reinforced concrete. metal, or wood that is
`joined with similar members in an overlapping pattern to form
`an arch or a vault.
`I lo'mel-9 I
`lamella arch
`[Cw ENG] An arch consisting basically of a
`series of intersecting skewed arches made up of relatively short
`straight members; two members are bolted, riveted, or welded
`to a third piece at its center.
`I l9'mel-9 ,i«irch I
`larnellar bone [n1sToL] Any bone with a microscopic struc-
`ture consisting of thin layers or plates.
`I la'mel-or jbon I
`lamellarchloroplast
`[cvTor_] A type of chloroplast in which
`the layered structure extends more or less uniformly through the
`whole chloroplast body.
`I la'mel-or ‘klc'>rra,plast I
`Iamellar crystal
`[CRYSTAL]
`A polycrystalline substance
`whose grains are in the form of thin sheets.
`I lo‘mel-or 'krist-
`al I
`[BUILD] A large span vault built of members
`lamella root
`connected in a diamond pattern.
`I lo'mel~9 Iriif I
`I lo‘mel-or
`Iamellar vector lleld See irrotational vector field.
`'vek't9r ,tEld I
`[mv zoo]
`Lamelllbranchiata
`valvia.
`I lo.mel~o,bra13-ké'ad-9 I
`
`LAMINAR FLOW
`
`pine
`Laminar flow in a circular pipe. In
`this case the velocity adjacent to
`the wall is zero and increases to a
`maximum in the center of the
`pipe.
`
`An equivalent name for Bi-
`
`l
`
`.15-
`
`Lamellisabellidae [nzv zoo] A family of marine animals.
`the order Thecancphria.
`I lo,mel's-s9'bel-o,dé I
`"1
`Lamé polynomials
`[MATH] Polynomials which result wh
`certain parameters of Lamé functions assume integral value‘?
`and which are used to express physical solutions of Laplace»
`equation in ellipsoidal coordinates.
`I la‘ma ,p'eil‘a'n6-mega‘? S
`Lamé’s equations
`[MATH] A general collection of seC0n‘d
`order differential equations which have five regular Singulafi.
`lies.
`I
`l2'i‘m:'rz i,kwa~zh9nz I
`‘
`Lamé’s relations
`[MATH]
`Six independent relations which
`when satisfied by the covariant metric tensor of a three»dimen_
`sional space provide necessary and sufficient conditions for the
`space to be euclidean.
`I lii'maz ri,la-shonz I
`Lamé wave functions
`[MATH] Functions which arise when
`the wave equation is separated in ellipsoidal coordinates, A150
`known as ellipsoidal wave functions.
`I
`la'm2't
`'wav |f;;[Jk_
`shonz I
`Lamiaceae
`[BOT] An equivalent name for Labiatae
`me’as~é,é I
`[BOT] An order of dicotyledonous plants in the
`Lamiales
`subclass Asteridae marked by its characteristic gynoecium. con.
`sisting ofusually two biovulate carpels, with each Carpel divided
`between the ovules by a false partition. or with the two halves
`of the carpel seemingly wholly separate.
`I
`,la-m<‘:'a-léz I
`lamina [BOT]
`See blade.
`[war] A thin sheet or layer of
`tissue; a scalelike structure.
`[GEOLI A thin. clearly differen.
`tiated layer of sedimentary rock or sediment. usually less than
`1 centimeter thick.
`[MATER] A fiat or curved arrangement of
`unidirectional or woven fibers in a matrix.
`I ‘lam-3-no I
`lamina cribrosa [ANAT]
`1. The portion of the sclera which
`is perforated for the passage of the optic nerve.
`2. The fascia
`covering the saphenous opening in the thigh.
`3. The anterior
`or posterior perforated space of the brain.
`4. The perforated
`plates of bone through which pass branches of the cochlear part
`of the vestibulocochlear nerve.
`I ‘lamia-no kr9'br6'so I
`laminal placentation [BOT] Condition in which the ovules
`occur on the inner surface of the carpels.
`I
`‘lam-9n~9l
`,plas'
`9n‘t5~shan I
`2. Pertaining
`1. Arranged in thin layers.
`laminar
`[sci TECH]
`'lam~o-nor I
`I
`to viscous streamline flow without turbulence.
`laminar boundary layer
`[FL MECH] A thin layer over the
`surface of a body immersed in a fluid, in which the fluid velocity
`relative to the surface increases rapidly with distance from the
`surface and the flow is laminar.
`I ‘lam-9-not ’baun-dré ,l2‘i-or I
`laminar composite [MATER] A composite material that con-
`sists of two or more layers of different materials that are bonded
`together.
`I ‘lam-9-nor kom'paz-at I
`laminar flow [FL MECH] Streamline flow of an incompressi-
`blct viscous Newtonian fluid; all particles of the fluid move in
`distinct and separate lines.
`[ ‘lame-nor ’fl6 I
`laminar flow control
`[AERO ENG] The removal of a small
`amount of boundary-layer air from the surface of an aircraft
`wing with the result that the airflow is laminar rather than tur-
`bulent; frictional drag is greatly reduced.
`I
`‘lam~a-nor 'fi5
`kon,trol I
`[nor] An order of brown, large, structurally
`Laminariales
`complicated, often highly differentiated members, commonly
`called kelps. of the algal class Phaeophyceae: distinctive fea-
`tures include a life history in which microscopic. filamentous.
`dioecious gametophytes allemate with a massive, parenchym—
`atous sporophyte, and a mature sporophyte typically consisting
`of a holdfastt stipe. and one or more blades.
`I
`,lam-o,nar~é‘?1‘
`léz I
`Laminariophyceae [BOT] A class of algae belonging to the
`division Phaeophyta.
`I
`,larn-iInar-E-o‘fis-é,é I
`laminar sublayer
`[FL MECHI The laminar boundary layer
`underlying aturbulcnt boundary layer.
`I ‘lam-9-nor ‘sab,l2‘t°9r l
`laminar wing
`[AERO ENG] A low—drag wing in which the
`distribution of thickness along the chord is so selected as I0
`maintain laminar flow over as much of the wing surface as
`possible.
`I ‘lam-3-nor ‘win I
`laminate [MATER] A sheet of material made of several differ—
`ent bonded layers.
`I ‘lam'o,nat I
`laminated composite
`[MATER] A Composite material con—
`sisting of layers of various materials.
`I
`'lam-e,nad-ad kam‘p‘c'lZ'
`at I
`[ELEC] Switch contact made up of a num-
`laminated contact
`ber of laminations, each making individual Contact with the
`opposite conducting surface.
`I
`'lam°o,nad~9d ‘kan,takt I
`
`HP 1009
`Page 3 of 4
`
`

`
`|aminated core
`
`|aminated core IELECTROMAGI An iron core for a coil trans-
`former, armature, or other electromagnetic device. built up from
`Iaminations stamped from sheet iron or steel and more or less
`Insulated from each other by surface oxides and sometimes also
`by application of varnish.
`I ‘lam-9,nad-ad ‘kor I
`|aminated glass See nonshattering glass.
`I
`‘lam-o,nad~:;d
`‘glas
`Iaminated metal
`[MET] A sheet or bar of composite metal
`composed of two or more bonded layers.
`I ‘lam-a,riad-ad ‘med-
`al I
`|aminated plastic [MATER] _A thin sheet made of superposed
`layers of plastic bonded or impregnated with resin or com-
`pressed under heat.
`I ‘larn-o,nad-ed ‘plas-tik I
`4
`|aminated spring [DES ENG] A flat or curved spring made of
`thin superimposed plates and forming a cantilever or beam of
`uniform strength.
`I ‘lam-a,nad-od ‘sprin I
`laminated wood [MATER] Board or timber composed of lay-
`ers of‘\1Nooddg}lued together with the grains parallel.
`I ‘lam-a-
`,nad-9 ‘Wu
`lamina terminalis
`[ANAT] The layer of gray matter in the
`brain connecting the optic chiasma and the anterior commrssure
`where the latter becomes continuous with the rostral lamina.
`I ‘lam-o-no ,t9r-ma'n2'il-is I
`I
`_
`I
`lamination [GRAPHICS] A plastic protective film on a printed
`sheet thathas been bonded by heat and pressure.
`[MATERI One
`of the thin punchings of iron or steel used in building up a
`laminated core for a magnetic circuit.
`[MED] An operation in
`embryotomy in which the skull is cut in slices.
`[SC] TECH]
`Arrangement in layers.
`I ‘lam-a,na~sh9n I
`'
`laminectomy [MED] Surgical removal of the lateral portion
`of the neural arch from one or more vertebrae.
`I
`,lam-9‘nek-
`ta-me I
`,larn-a‘nag-ra~tE I
`I
`Iaminography See sectional radiography.
`Laml‘s theorem [MEcr-t] When three forces act on a particle
`in equilibrium. the magnitude of each is proportional to the sine
`of the angle between the other two.
`I la‘méz ,thir-om I
`lamp [ENG] A device that produces light. such as an electric
`lamp.
`I lamp I
`lampadite [MINERAL] A mineral composed chiefly of hydrous
`manganese oxide with as much as 18% copper oxide and often
`cobalt oxide.
`I ‘lam-pa,ditI
`lamp bank
`[ELEC] A number of incandescent lamps con-
`nected in parallel or series to serve as a resistance load for full-
`load tests of electric equipment.
`I ‘lamp bank I
`lampblack [MATER] A grayish-black amorphous. practically
`pure form of carbon made by burning oil, coal tar, resin, or other
`carbonaceous substance in an insufficient supply of air; used in
`making paints. lead pencils, metal polishes. electric brush car-
`b0I1S. crayons. and carbon papers.
`I ‘lamp,hlak I
`lampbrush chromosome
`[CYTOL] An exceptionally large
`chromosome characterized by fine lateral projections which are
`ffssociated with active ribonucleic acid and protein synthesis.
`‘lamp .brash 'kr6-me,som I
`lamp cabin See lamp room.
`I ‘lamp kab-on I
`lamp-Charging rack [MIN ENG] Mine-lamp—charging racks
`Which allow miners to store lamp units for recharging after daily
`"55 l ‘lamp ,chiir~jir] ,rak I
`'3'“? cord [ELEC] Two twisted or parallel insulated wires,
`usually no. 18 or no. 20. used chiefly for connecting electric
`Iequlpment to wall outlets.
`I ‘lamp ,kord I
`_
`amp depreciation [ELEC] The decrease in amount of light
`Elrprtted by a lamp during its operating life.
`I ‘lamp di,prE-
`’ Eifrshon I
`kllmphorder
`[ELECI A device designed to connect an electric
`r
`:“}P l0 a circuit and to support it mechanically.
`I
`'larnp,h6ld~
`"'"'t_Ihouse
`[mo]
`1. The light housing in a motion picture
`Pmleclflr, located behind the projector head ordinarily consist-
`“‘g 0f 8 carbon arc lamp operating on direct current at about 60
`V°1‘5. a concave reflector behind the are which collects the light
`a“_d C0YlCent.rates it on the film, and cooling devices.
`2. A box
`Wm‘ 3 small hole containing an electric lamp and a concave
`mimlf behind it, used as a concentrated source of light in a
`m,l°‘°SC0pe, photographic enlarger. or other
`instrument.
`all
`la'f1P.haus I
`r'“P|ng
`[MIN ENG] Use of a portable ultraviolet lamp to
`a:"e“_l fluorescent minerals in prospecting.
`I ‘lam-pir] I
`8
`P ‘Mush current
`[ELEc] The sur e of current that occurs
`
`Lanceolidae
`
`1105
`
`I {lamp ‘in,resh Ikor
`
`LAMPRIDIFORMES
`
`Oarfish (Regalecus glesne); length
`to over 20 feet (6 meters).
`
`LAMPYHIDAE
`
`Drawing of a firefly beetle. (From
`7‘. I. Storerr and R. L. l/singer,
`General Zoology, 3d ed., Mc-Gmw.
`Hill, 1957)
`
`when an incandescent lamp is turned on.
`ant I
`lampman [MIN ENG] A person responsible for maintaining
`and servicing miners‘ lamps.
`I ‘lamp-man I
`lamp oil See kerosine.
`I ‘lamp ,oil
`I
`lamprey IVERT zoo] The common name for all members of
`the order Petromyzonida.
`I ‘lam-pré I
`Lampridiformes
`[VERT zoo] An order of teleost fishes char-
`acterized by a compressed. often ribbonlike body. tins composed
`of soft rays. a ductless swim bladder. and protractile maxillae
`among other distinguishing features.
`I Ilam~prid-9‘for,mez I
`lamprobolite See basaltic hornblende.
`I
`,lam-pr9'b6,lit I
`Lamprocystis
`IMICROBIOI A genus of bacteria in the family
`Chromatiaceae; cells are spherical and motile. have gas vacu-
`oles. and contain bacteriochlorophyll a on vesicular photosyn-
`thetic membranes.
`I
`,lam-pra‘sis-tos I
`lamp room [mm ENG] A room or building at the surface of a
`mine for charging. servicing, and issuing all cap, hand. and flame
`safety lamps. Also known as lamp cabin;
`lamp station.
`I
`'lamp ,ri_im I
`IMICROBIOI A genus of gram-negative. obli-
`Lampropedia
`gatcly anaerobic cocci of uncertain affiliation; cells form pairs.
`tetrads. or flat squared tablets.
`I
`,lam-prs‘péd-E-9 I
`lamprophyllile
`IMINERALI Na2SrTiSi3O,5 A mineral com-
`posed of titanium strontium sodium silicate.
`I
`,lam-pre‘ti,lit I
`lamprophyre IPETRI Any of a group of igneous rocks char-
`acterized by a porphyritic texture in which abundant, large crys-
`tals of dark—t-olored minerals appear set in a not visibly crystal-
`line matrix.
`I ‘larntpro,fi-or I
`lampshade paper
`[MATERI Paper that is translucent and ei-
`ther llanre-resistant or flame—reta.rdant: often made of wood pulp.
`vegetable parchment, or laminated glassine.
`I
`'lamp,shad ,pa-
`P9r I
`I ‘larnp ,sta-shan I
`lamp station See lamp room.
`Lampyridae [nw zoo] The firefly beetles, a large cosmopol-
`itan family of coleopter-an insects in the supcrfamily Cantharo-
`idea.
`I lam'pir-9,dé I
`LAN See local-area network.
`I lan I
`lanac [NAV] A proprietary navigation system that depends on
`secondary radar to aid airplanes to avoid midair collisions and
`maintain a specified altitude prior to landing. Derived from
`laminar, air navigation. and collision.
`I
`'la,nak I
`Lanarkian IGEOLI A European stage of geologic time forming
`pan of the lower Upper Carboniferous, above Lancastrian and
`below Yorkiamequivalent to lowermost Westphalian.
`I
`l9‘n‘2ir~
`ké-an I
`[MINERAL] Pb2OSO4 A white, greenish, or gray
`lanarkite
`monoclinic mineral consisting ofbasic lead sulfate, with specific
`gravity of 6.92; formed by action of heat and air on galena.
`I ‘lan'ar,kit I
`lanaloside IBIOCHEMI Any of three natural glycosides from
`the leaves of Digitalis lanata; on hydrolysis with acid, it yields
`one molecule of I)—glucose, three molecules of digitoxose, and
`one molecule of acetic acid; all three glycosides are cardioactive.
`I l9‘nad-9,sid I
`[MEcn ENG] A cylindrical steam boiler
`Lancashire boiler
`consisting oftwo longitudinal furnace tubes which have internal
`grates at the front.
`I ‘lag-ka-shir ,boilvar I
`Lancastrian IGEOLI A European stage of geologic time form-
`ing part of the lower Upper Carboniferous, above Viséan and
`below Lanarkian.
`I laI_]'kas-tré-an I
`lance [MED] To cut or open, as with a lancet.
`into but not through the piece of work.
`I lans I
`Lance
`IORDI A surface-to-surface missile that has inertial
`guidance and a liquid propulsion system, to provide artillery
`support for infantry, armored. mechanized, and airborne divi-
`sions.
`I lans I
`lance door
`[MECH ENG] The door to a boiler furnace through
`which a hand lance is inserted.
`I ‘lans ,dor I
`Lanceiield groups
`[MlCROBlO] Antigenically detemiined
`categories .for classification of
`I3—hemolytic
`streptococci.
`I ‘lans,fEld ,griips I
`lancelet
`[zoo] The common name for members of the sub-
`phylum Cephalochordata.
`I ‘lans-lat I
`Ianceolate IBIOLI Shaped like the head of alance.
`9,lat I
`Lanceolidae [rNv zoo] A family of bathypelagic amphipod
`crustaceans in the suborder Hyperiidea.
`I
`,lan-sé'iil-a_dé I
`
`[MET] To cut
`
`I ‘lan-sé-
`
`HP 1009
`Page 4 of 4