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`
`
`
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`
`
`MIEEIIAW-Hlll
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`Slnmiln
`In:mm:m
`mums
`fifth fllilinn
`
`
`
`Sybil P. Parker
`Editor in Chief
`
`McGraW-Hill, Inc.
`
`

`
`
`
`
`
`
`
`..,.-..._>.'v
`
`On the cover: Photomicrograph of crystals of vitamin B1.
`(Dennis Kunkei, 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—Hi11, Inc.
`Allrights reserved. J. Quick,Artisrs’ andIllustrators’ Encyclopedia, Cop 'ght © 1969 by McGraw-Hill, Inc. All
`rights reserved.Blakision'sGouldMedicalDictionary, 3ded., Copyright © 1956, 1972by McGraw-Hil1,1nc. All
`rights reserved. T. Baurneister and L. S. Marks, eds., Standard Handbookfor Mechanical Engineers, 7th ed.,
`Copyright @ 1958, 1967 by McGraw—Hil1, Inc. All rights reserved.
`In addition, material has been drawn from the following references: R..E. Huschlce, Glossary ofMeteorology,
`American Meteorological Society, 1959; U.S. Air Force Glossary ofStandardized Terrns,"AF Manual 11-1, vol.
`1, 1972; Cornmunications-Electronics Terminology, AF Manual 1le1,_.vo1. 3, 19.70; W. H. Allen, ed., Dictionary
`ofTechnical Termsfor Aerospace‘ Use, 1st ed., National Aeronautics and Space Adrninistration, 1965; J. M.
`Gilliland, Solar-TerrestrialPhysics.‘ A Glossary ofTerms andAbbreviations,Royal AircraftEstablishmentTech-
`nical Report 67158, 1967; Glossary ofAir Traffic 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 ofDefense, 1967‘. P. W. Thrush, comp.
`and ed.,A Dictionary ofMining, Mineral. andRela!edTerms, Bureau ofWoes, 1968;NuclearTerms:A Glossary,
`2d ed., Atomic Energy Commission; F. Casey, ed., Compilation ‘ofTerms in Information Sciences Technology,
`Federal CouncilforScience andTechnology, 1970; GlossaryofStinfoTerminology,Office ofAerospaceResearch,
`U.S. AirForce, 1963; Naval Dictionary ofElectronic, Technical, andImperative Terms, Bureau ofNaval 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, 1.978, 1976, 1974by McGraw-Hill, Inc. Allrights reserved. PrintedintheUnited
`States of America. Except as permitted under the United States Copyright Act of 1976, no part ofthis publication
`may be reproduced ordistributed in any form or by any means, or stored in adatabase orretrieval system, without
`the prior written permission of the pubiisher.
`‘
`
`4567890
`
`DOW/DOW
`
`998_
`
`ISBN 0-0704-2333-4
`
`Library of Congress Cataloging-in—Publication Data
`
`2. Techno1ogy—~Dictionaries.
`
`McGraw—Hii§ dictionary of scientific and technical terms I
`Sybil P. Parker, editor in chief..——5th ed.
`p.
`cm.
`ISBN 0~07—042333-4
`1. Science——Dictionaries.
`1. Parker, Sybil P.
`QI23.M34
`1993
`503——dc20
`
`-
`
`93-34772
`CIP
`
`INTERNATIONAL EDITION
`
`

`
`
`
`porphyry
`
`
`
`_
`
`PORTUGUESE MAN-OF-WAFI
`
`
`
`Float and tentacles of a
`Portuguese rnan—of-war. (From
`
`sedimentary rock in which the constituent crystals are of more
`than one size and in which larger crystals are enclosed in a finer-
`graincd matrix. Also lcnownas porphyrocrystallic.
`{ porlfir
`oltiip-ilc ]
`porphyry [PETR] An igneous rock in which large phenocrysts
`are enclosed in a very-fine-grained to aphanitic matrix. For»
`mcrly known as porphritc.
`{
`'por-fa-re }
`porpoise [VERT zoo} Any of several species of marine mam-
`mals of the family Phocaenidae which have smali flippers, a
`highly developed sonar system, and smooth, thick, hairless skin.
`[ ‘por-pas }
`[MATER] A pale-yellow fatty oil obtained from
`porpoise oil
`blubber of the brown porpoise; soluble in ether, benzene, carbon
`disulfide, and -chloroform; used as a lubricant, leather dressing,
`and illuminating oil, and in soap stock.
`[ ‘pox-pas ,oii i
`Forro prism [omcs] One of two identical prisms used in the
`Form prism erecting system; it is a right-angle prism with the
`corners rounded to minimize breakage and simplify assernbiy.
`{ ‘po-ro ,priz-om }
`Porro-prlsm erecting system [OPTICS] A compound erect-
`ing system, designed by M. Form, in which there are four re-
`fiections to Completely erect the image; two Porro prisms are
`employed; the line of sight is bent through 360“, is displaced.
`but is not deviated; used in prism binocuiars and some tciescope
`systems.
`{ ‘po-to ,priz-om i'rek-tin ,sis-tom ]
`port
`[COMPUT SCI] An interface between a communications
`channel and a unit of computer hardware.
`[ELEC] An entrance
`or exit for a network.
`[ELECTROMAG] An opening in a wav-
`eguide component, through which energy may be fed or with-
`drawn, or measurements made.
`[ENG] The side of a ship or
`airplane on the left of a person facing forward.
`[ENG Acous]
`An opening in a bass-reflex enclosure for a loudspeaker, de-
`signed and positioned to improve bass response.
`[cnooa] See
`harbor.
`[NAV ARCH] An opening -in a vessel to provide access
`for passengers, cargo handling, discharging water, and so forth.
`[nuccuo] An opening in a research reactor through which
`objects are inserted for irradiation or from which beams of
`radiation emerge for experimental use.
`[ port }
`portability [COMPUT SCI] Property of a computer program that
`is sufficiently flexible to be easily transferred to run on a com-
`puter of a type different from the one for which it was designed.
`[ ,pord-o'bil-od-e ]
`portable
`[ENG] Capable of being easily and conveniently
`transported.
`{ 'pord-9-bal}
`portable audio terminal
`[cornrur SCI] A lightweight, self-
`contained computer terminal with a typewriter keyboard, which
`can be attached to a telephone line by placing the telephone
`handset in a receptacle in the terminal.
`{
`'pord-9-bai ‘od-5-6
`,to1rn-on-oi }
`[cornrur SCI] . A computer terminal
`portable data terminal
`that can be carried about by hand to collect data from remote
`locations and to transfer this data to a computer system.
`{ 'pord-
`9-bol ‘dad-9 ,tor-rnon'cl ]
`porta hepatic
`[ANAT] The transverse fissure of the live:
`through which the portal vein and hepatic artery enter the liver
`and the hepatic ducts leave.
`[
`'pord-o he‘pad-as }
`2.
`portal
`[ANAT]
`1. Of or pertaining to the porta hepatis.
`Pertaining to the portal vein or system.
`[ENG] A redundant
`frame consisting of two uprights connected by a third member
`at the top.
`[MJN ENG]
`1. An entrance to a mine. 2. The rock
`face at which a tunnel is started.
`[ ‘pord-oi }
`portal circulation {H-ivsro] The passage of venous blood
`through a-portal-system.
`[
`'pord-oi ,sor-kyo'la-shon }
`porlalclrrhosis [Mao] Replacementofnonnalliverstmcture
`by abnormal lobuies of liver cells, often hype:-plastic, delimited
`by bands of fibrous tissue, giving the gross appearance of a
`finely nodular surface. Also known as l..aennec's cirrhosis.
`{ ‘pord-al se"1'frsos }
`'
`portal crane [Mncn ENG] Ajib crane carried on afour-legged
`portal built to run on rails.
`[
`'pord-91 ‘kran }
`portal hypertension [MED] Portal venous pressure in excess
`of 20 mi-nHg (2666 pascals), resulting from intrahepatic or ex-
`
`posistor
`
`Porterfleld {ceo1.] A North American geologic stage of the
`Middle Ordovician, forming the lower division of the Mo-
`hawkian, and lying above Ashby and below Wilderness
`”
`{
`'pord'or,fEld}
`[soup srxrsj The effect of
`Portevirr-Le Chatelier effect
`foreign atoms on the deformation curve of a materiai, in which
`steps appear in what was initially a smooth curve.
`[
`:po1-[Ivan
`lo,shat'lE‘ai,feltt ]
`,
`3
`port expander
`[COMPUT SCI] Equipment that connects 1”
`to several other devices to one port in a computer.
`[
`"P611
`il(,span-dar ]
`porihole
`[DES ENG] The opening or passageway connecting
`the inside of a bit or core barrel to the outside and through which
`the circulating medium is discharged.
`[ENG] A circular open-
`ing in the side of a ship or airplane, usually serving as a window
`and containing one or more panes of glass.
`[
`'port,hoi }
`porthole die
`[MET] An extrusion die having two or more
`sections in which metal is extruded separately in each section
`and welded before leaving the die to form intricate hollow
`shapes.
`[
`'port,hol ,di }
`Portia
`[ASTRON] A satellite of Uranus orbiting at a mean
`distance of 41,070 miles (66,100 kilometers) with a period of
`12 hours 21 minutes, and with a diameter of about 68 miles (110
`lcjiometers).
`{ 'por-she }
`portico [ARCH] A colonnade or other sheltered place to walk
`in.
`{ 'pord-a,k5 }
`porting [COMPUT sci] The process of converting software to
`run on a computer other than the one for which it was originally
`written.
`[
`'pord-it} }
`portland cement
`[MATER] A hydraulic cement made of pul-
`verized, calcined argillaccous and calcareous materiais;
`the
`proper name for ordinary cement.
`[ "port-lend si'rnent }
`Portlandlan [GEOL] A European geologic stage of the Upper
`Jurassic, above Kimmeridgian, below Bcrriasian of Cretaceous.
`{ port'land-e-on ]
`portlandlte
`[MINERAL] Ca(OH),_ A colorless, hexagonal
`mineral consisting of calcium hydroxide; occurs as minute
`plates.
`{ 'pC')1‘t~1on,dit}
`{MATER] Portland cement to
`portland-pozzolana cement
`which pozzolana has been added, in the amount of about 20%,
`to reduce the liability of leaching.
`l
`‘port-land ,piit-sa‘léin-9
`_
`si‘ment ]
`[MATER] A type of oolitic limestone that
`portland stone
`consists of fossils cemented together with lime; found only on
`the Isle of Portland, Dorset, England.
`{ {port-land ‘ston }
`port of entry [CIV ENG] A location for clearance of foreign
`goods and citizens through a custornhouse.
`{ ‘port ov ‘en-tie l
`port operations service [COMMUN] Maritime mobile com-
`munications service in or near a port, between coast stations and
`ship stations, or between ship stations, in which messages are
`restricted to those relating to the movement and safety of ships
`and, in an emergency, to the safety of persons.
`{ ‘port ,iip'9'I5'
`shonz ,sor-vos ]
`portrait
`[GRAPHICS] A printing orientation in which the
`printed lines are parallel to the narrow side of the paper.
`l
`'P9F'
`trot }
`‘
`Portuguese man-oi-war
`[nvv zoo] Any of several brilliantly’
`colored tropical siphonophores in the genus Physalia which
`possess a large float and extremely long tentacles.
`[
`.130?
`cha'géz {man cv 'wor }
`.
`Portulacaceae [nor] A family of dicotyledonous plants 111
`the order Caiyophyllales distinguished by a syncarpous gyn0f=-
`cium, few, cyclic tepals and stamens, two sepals, and W0 W
`many ovules.
`{
`,por-cha-1a‘i(as-e,E }
`Portunidae [1.Nv zoo] The swimming crabs, a family of the
`Brachyura having the‘ last pereiopods modified as swunmlfig
`paddles.
`{ por'tii-no,dé }
`port-wine stain ‘[Mr:o] A congenital hemangiorna cha1'acfB1"
`ized by one or more red to purplish patches, usually on the face.
`{ 'port ,win ,stan }
`lass
`Porulosida
`[aw zoo] An order of the protozoan subc