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Total record count: 6269.

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Eng ID Term Definition
281
astronomy: nautical (or navigational)
ASTRONOMY as applied to NAVIGATION.
282
atlas
A collection of CHARTS or MAPS to be kept (loose or bound) in a volume.
283
atmosphere
Gaseous envelope which surrounds the EARTH. The gaseous envelope surrounding any STAR, PLANET, etc. A unit of pressure, equal to the pressur... more
Gaseous envelope which surrounds the EARTH. The gaseous envelope surrounding any STAR, PLANET, etc. A unit of pressure, equal to the pressure exerted per square centimetre by a column of mercury 760 mm high at a temperature of 0°C when the ACCELERATION OF GRAVITY is 980.665 centimetres per SECOND squared..
284
atmosphere: free
That part of the ATMOSPHERE above the FRICTION LAYER, in which the air motion is affected to a negligible degree by surface friction.
285
atmosphere: ICAO
STANDARD ATMOSPHERE adopted by the International Civil Aviation Organization (ICAO). Its main features are mean sea-level pressure of 1013.2... more
STANDARD ATMOSPHERE adopted by the International Civil Aviation Organization (ICAO). Its main features are mean sea-level pressure of 1013.25 mb, and a temperature lapse rate of 6.5° C/km from surface to the TROPOPAUSE situated at 11 km.
286
atmosphere: standard
Conventional reference atmosphere, chosen to represent in a simple way the approximate average condition in the VERTICAL.
287
atmospheric
ELECTROMAGNETIC WAVE resulting from an electric discharge (LIGHTNING) in the ATMOSPHERE.
288
atmospheric drag
A major perturbation of close artificial satellite orbits by the resistance of the atmosphere.
289
atmospheric pressure
See PRESSURE.
290
atmospheric refraction
See REFRACTION.
291
atmospheric window
The region in the radiation spectrum containing wavelengths between 8.5 and 11 micrometers, which are not absorbed to any great extent by at... more
The region in the radiation spectrum containing wavelengths between 8.5 and 11 micrometers, which are not absorbed to any great extent by atmospheric gases. In the absence of cloud, terrestrial radiation of this wavelength is lost to space, enabling the cooling of the earth to take place. Other narrower wavebands also do not absorb long-wave radiation, but these are of less importance in this context.
292
atoll
A coral ISLAND consisting of a ring-shaped REEF nearly or entirely surroun­ding a central LAGOON.
293
atom
The smallest particle of an element which can enter into a chemical combination.
294
atomic clock
See CLOCK.
295
Atomic Time: International
The time reference coordinate established by the Bureau International de l'Heure on the basis of atomic clocks.
296
attenuation
A lessening in amount, particularly the reduction of the AMPLITUDE of a WAVE or the intensity of light or SOUND with distance from the origi... more
A lessening in amount, particularly the reduction of the AMPLITUDE of a WAVE or the intensity of light or SOUND with distance from the origin.
297
audiofrequency
A FREQUENCY within the audible RANGE, about 20 to 20.000 CYCLES per SECOND. Also called sonic frequency.
298
aurora
Luminous PHENOMENON which appears in the high ATMOSPHERE, mainly in high LATITUDES, in the form of RAYS, arcs, bands, draperies, or CORONA. ... more
Luminous PHENOMENON which appears in the high ATMOSPHERE, mainly in high LATITUDES, in the form of RAYS, arcs, bands, draperies, or CORONA. Also called polar aurora.
299
aurora australis
AURORA of the southern hemisphere.
300
aurora borealis
AURORA of the northern hemisphere.