m Metre(s), SI unit of length (3.28084 feet.)
M or Mach number The ratio of the speed of a body to the speed of sound (340 m; 1 116 ft/s in air at 15 degrees C) under the same ambient conditions.
MAD Magnetic anomaly detector.
mass balance Mass attached to flight control surface, typically ahead of hinge axis, internally or externally, to reduce or eliminate coupling with airframe flutter modes.
mass flow Mass of air passing per second (usually at T-O, S/L).
MAWS Missile-approach warning system.
mb Millibar, bar x 10-3.
MBB Messerschmitt Bolkow Blohm (Germany).
McDD McDonnell Douglas (US). Also MD or MDD.
MCM Mine countermeasures.
medevac Medical evacuation.
MFD Multifunction (electronic) display.
MFI mnogofunktseeonahl’nyy frontovoy istrebeetel = multi-role tactical fighter.
MHz Megahertz: 1 million (106 ) Hertz.
Mi Mil (Russian design bureau).
MICA Missile d’Interception et de Combat Aerien = combat and air-intercept missile.
microlight See ultralight.
MIDS Multifunction information distribution system.
MiG Mikoyan-Guryevich (Russian design bureau). Also Mikoyan-Gurevich.
MKR Marker beacon receiver.
MLS Microwave landing system.
MLU Mid-life update.
MLW Maximum landing weight.
mm Millimetres, metres x 10-3.
MMO Maximum operating Mach number.
MMS Mast-mounted sight.
MMW MilliMetric (or MilliMetre) Wave (as AN/APG-78 Longbow radar for the AH-64D Apache Longbow helicopter).
MoD Ministry of Defence.
monocoque Structure with strength in outer shell, devoid of internal bracing (semi-monocoque, with some internal supporting structure).
MoU Memorandum of Understanding.
MPA Maritime patrol aircraft.
mph Miles per hour.
MR Maritime Reconnaissance (UK designator).
MRA Maritime Reconnaissance and Attack (UK designator).
MRCA Multi-Role Combat Aircraft (re-named Tornado).
MRT Multi-Role Transport.
MRTT Multi-Role Taneker/Transport.
MSIP Multistage/d improvement program (US).
MTBF Mean time between failures.
MTI Moving-target indication (radar).
MTOW Maximum take-off weight (minus taxi/run-up fuel).
MTU Motoren und Turbinen Union (Germany).
MYP Multiyear procurement (US).
MZFW Maximum zero-fuel weight.