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the volume (of sound) to make some-thing such as a radio quieter or less loud

lower airspace /l.υ. e.spe.s/
noun the airspace below FL245 (approximately 24,500 ft)

lower atmosphere /l.υ.
tm.sf../ noun the layer of the atmosphere in which changes in the weather take place. Also called tropo-sphere
low frequency /l.υ frikw.nsi/, low frequency band /l.υ frikw.nsi bnd/ noun a radio communications range of frequencies between 30–300 kHz. Abbreviation LF
lubricate /lubr.ke.t/ verb to oil or to grease moving parts in order to reduce friction . Oil passes through the hollow crankshaft to lubricate the big-end bearings. . Turbo chargers are lubri-cated by the engine oil system.
lubrication /lubr.ke..(.)n/ noun
the act or process of covering moving surfaces with oil or grease in order to reduce friction . lubrication system the tank, pipes, pumps, filters, etc., which together supply oil to moving parts of the engine
luggage /l.d/ noun baggage, i.e. cases and bags that somebody takes when travelling

M

m1 abbreviation metre m2 abbreviation minute Mach /mk/ noun the ratio of the
speed of an object to the speed of sound in the same atmospheric conditions .
Mach 2 equals twice the speed of sound.
COMMENT: Named after E. Mach, the Austrian physicist who died in 1916.

machine /m..in/ noun a device with fixed and moving parts that takes mechanical energy and uses it to do use-ful work . A drill is a machine for mak-ing holes in things. . An electrical cir-cuit is designed to carry energy to a particular device or machine which can then perform useful work.
Machmeter /mkmit./ noun an
instrument for measuring the Mach
number of an aircraft Mach number /mk/ noun a number that expresses the ratio of the speed of an object to the speed of sound
magnesium /mnizi.m/ noun a
light, silvery-white metallic element that burns with a brilliant white flame. Symbol Mg (NOTE: The atomic number of magnesium is 12.)
magnesium flare /mnizi.m fle./ noun a device for distress signal-ling at night . to send off magnesium flares
magnet /mn.t/ noun an object that produces a magnetic field, and attracts iron and steel . Magnetism in a magnet appears to be concentrated at two points called the poles.
magnetic /mnet.k/ adjective
referring to or having the power of a magnet or something with a magnetic
field . A freely suspended magnet – not influenced by outside forces – will align itself with the Earth’s magnetic lines of force which run from the north mag-netic pole to the south magnetic pole.
magnetic bearing /mnet.k
be.r../ noun the angle measured in a clockwise direction of a distant point, relative to magnetic north
magnetic declination /mnet.k dekl.ne..(.)n/ noun same as mag-netic variation . To convert magnetic bearing into true bearing it is necessary to apply magnetic variation at the point at which the bearing was taken.