Specified CommandA command that has a broad continuing mission and that is established and so designated by the President through the Secretary of Defense with the advice…
specimena real-world example of how the mark is actually used on goods or in the offer of services.
Specimen BallotAn official ballot made available for public inspection; an official ballot for each ballot format used in each election must be designated a specimen…
SpeckleImperfections in an image as a result of scanning paper documents that do not appear on the original. See De-speckling.
speckle patternIn optical systems, a field-intensity pattern produced by the mutual interference of partially coherent beams that are subject to minute temporal and…
SPECTA special type of computed tomography (CT) scan in which a small amount of a radioactive drug is injected into a vein and a scanner is used to make…
SpectraA range of different measurements. In terms of physics, spectra usually refers to the different wavelengths, or colors (if in the visible range) of light…
Spectral IrradianceThe monochromatic irradiance of a surface per unit bandwidth at a particular wavelength, usually expressed in Watts per square meter-nanometer bandwidth.
Spectral karyotype (SKY)A visualization of all of an organism's chromosomes together, each labeled with a different color.
Spectral LineAn emission (bright) or absorption (dark) of light at a specific frequency or wavelength.
spectral loss curveOf an optical fiber, a plot of attenuation as a function of wavelength. Note: Spectral loss curves must be normalized with respect to distance before…
spectral purityThe degree to which a signal is monochromatic.
spectral radianceRadiance per unit wavelength interval at a given wavelength, expressed in watts per steradian per unit area per wavelength interval.
Spectral ReflectanceThe ratio of energy reflected from a surface in a given waveband to the energy incident in that waveband.
spectral responsivityThe ratio of an optical detector's electrical output to its optical input, as a function of optical wavelength.
Spectral Wave DensityOn a buoy report, energy in (meter*meter)/Hz, for each frequency bin (typically from 0.03 Hz to 0.40 Hz).
Spectral Wave DirectionOn a buoy report, mean wave direction, in degrees from true North, for each frequency bin.
spectral widthA measure of the spread of the Doppler spectrum and consequently is sensitive to the spread in the particle size spectra.
Spectrally Selective CoatingsA type of window glazing films used to block the infrared (heat) portion of the solar spectrum but admit a higher portion of visible light.
SpectrographA device that separates light by wavelength (color) in order to produce a spectrum that allows for the identification of elements within the light source.
spectroscopy(spek-TRAH-skoh-pee) The study of the amount of light that is taken up, given off, or scattered (reflected) by an object.
SpectrumElectromagnetic radiation arranged in order of wavelength from Ion wavelength radio waves to short wavelength gamma rays.
Spectrum intensityThe integral of the pseudo-velocity response spectrum taken over the range of significant structural vibration periods of the structure being analyzed.
Spectrum of HealthcareHealth services provided in a range of settings, including acute care hospitals, outpatient surgery centers, long-term acute care hospitals, long-term…
spectrum signatureThe pattern of radio signal frequencies, amplitudes, and phases, which pattern characterizes the output of a particular device and tends to distinguish it…
Spectrum WidthThis WSR-88D radar product depicts a full 360 degree sweep of spectrum width data indicating a measure of velocity dispersion within the radar sample…
Spectrum Width Cross SectionThis WSR-88D radar product displays a vertical cross section of spectrum width on a grid with heights up to 70,000 feet on the vertical axis and distance…
Specular reflectionAlso known as direct reflection, regular reflection, or mirror reflection. The reflection of electromagnetic rays without scattering or diffusion.
SpeculatorWhen you make a financial commitment because you believe something will happen in the market where you're trading that will provide a profit, you are…
speculum(SPEK-yoo-lum) An instrument used to widen an opening of the body to make it easier to look inside.
speech levelThe power in dBm of a speech signal measured using a technique equivalent to Method B of ITU-T Recommendation P.56. [T1.255-1997]
speech pathologist(... puh-THAH-loh-jist) A specialist who evaluates and treats people with communication and swallowing problems. Also called speech therapist.
speech privacyTechniques using fixed sequence permutations or voice/speech inversion to render speech unintelligible to the casual listener. [INFOSEC-99]
Speech RecognitionA technology that enables a machine to recognize spoken words. Speech recognition is not a biometric technology.
speech synthesizerA device that is capable of accepting digital or analog data and developing intelligible speech sounds that correspond to the input data, without…
speech therapistA specialist who evaluates and treats people with communication and swallowing problems. Also called speech pathologist.
speech-plusPertaining to a circuit that was designed and used for speech transmission, but to which other uses, such as digital data transmission, facsimile…
speech-plus-duplex operationOperation in which speech and telegraphy (duplex or simplex) are transmitted simultaneously over the same circuit, and mutual interference is eliminated…
speech-plus-signalingPertaining to equipment that permits the use of part of a voice-frequency band for signaling.
SPEEDSystem Planning, Engineering, and Evaluation Device.
speed callingA service feature that enables a switch or station to store certain telephone numbers and dial them automatically when a short (1-, 2-, or 3-digit) code…
speed dialing1. Synonym abbreviated dialing. 2. Dialing at a speed greater than the normal ten pulses per second.
speed of light (c)The speed of an electromagnetic wave in free space, precisely 299,792,458 m/s. Note 1: The preceding figure is precise because by international agreement…
speed of serviceThe time between release of a message by the originator to receipt of the message by the addressee, as perceived by the end user.
Speed ShearThe component of wind shear which is due to a change in wind speed with height, e.g.
Speedy Trial ActFederal law establishing time limits for carrying out major events, i.e. indictment, arraignment, etc., in a criminal prosecution.
speleothema mineral deposit formed in caves. Two types of speleothems are stalagmites and stalactites.
Spell CheckChecks an email message before sending allowing you to correct any spelling errors.
Spell Check OptimizationThe process of optimizing a spell check dictionary towards a live search index.
Spell checkingIndividual query terms and phrases are spell-checked against a dictionary. The spell check algorithm is normally based on the edit distance between a…
Spending planA spending plan can help you manage your money more effectively, live within your income limits, reduce your reliance on consumer credit, and save for the…
Spendthrift trustA trust set up for the benefit of someone whom the grantor believes would be incapable of managing his or her own financial affairs.
spent mediumAfter sub-culture, medium which is discarded because it has been depleted of nutrients, dehydrated, or accumulated toxic metabolic products.
sperm (spurm)The male reproductive cell, formed in the testicle. A sperm unites with an egg to form an embryo.
sperm banking (spurm...)Freezing sperm for use in the future. This procedure can allow men to father children after loss of fertility.
sperm competitionCompetition between different spermatozoa to fertilize the of a single female.
sperm count (spurm kownt)A count of the number of sperm in a sample of semen. A sperm count may be used as a measure of fertility.
sperm retrieval(spurm rih-TREE-vul) Removal of sperm from a man's testis or epididymis by a doctor using a fine needle or other instrument.
sperm sexingThe separation of mammalian sperm into those bearing an X chromosome and those bearing a Y chromosome, in order to be able to produce, via artificial…
spermatic cord(sper-MA-tik KORD) A cord-like structure in the male reproductive system that contains nerves, blood and lymph vessels, and the vas deferens (a coiled…
spermatidImmature spermatozoon. One of the four cells formed at the end of the second meiotic division in spermatogenesis.
spermatocyteThe premeiotic parental cell of the spermatids; the primary spermatocyte before the initiation of the first meiotic division; the secondary spermatocyte…
spermatogenesisThe series of cell divisions in the testis as a result of which the formation and the maturation of the male gametes (i.e. sperm) are achieved.
spermatogonium(pl.: spermatogonia) Primordial male germ cell. These can either divide by mitosis to produce daughter cells, or enter a growth phase and differentiate…
spermatozoon(Abbreviation: sperm). (pl.: spermatozoa) The mature, mobile gametic cell of male animals, produced in the testis.
SPFA scale for rating the level of sunburn protection in sunscreen products. The higher the SPF, the more sunburn protection it gives.
SPF (sender policy framework)An extension of the SMTP protocol that prevents spammers from forging the From: fields in e-mail messages by verifying that the IP address in the SMTP…
spharoblastNodule of wood which can give rise to adventitious shoots with juvenile characteristics.
sphenoid sinus(SFEE-noyd SY-nus) A type of paranasal sinus (a hollow space in the bones around the nose).
Sphere CalibrationReflectivity calibration of a radar by pointing the dish at a metal sphere of (theoretically) known reflectivity.
spheroplast(AlteRNA tive spelling: sphaeroplast). A microbial or plant cell from which most of the cell wall has been removed, usually by enzymatic treatment.
sphincterA ring-shaped muscle that relaxes or tightens to open or close a passage or opening in the body.