MDS  (.1.).Minimum.Discernible.Signal..The.MDS.is.the. lowest.RF.signal.level.that.can.be.detected.as.a. valid.signal... (.2.).Maintenance.Diagnostic.Systems
MDT  Maintenance.Display.Terminal
MEA  Minimum.En.route.Altitude
MEC  Main Equipment Center
MEL  Minimum Equipment List. The list of equipment that the FAA requires be aboard and working on an aircraft before flying.
MEMS  MicroElectroMechanical.Systems
MEO  Medium Earth Orbit
MES  Main.Engine.Start
MET  Meteorology
MF  Medium Frequency. The portion of the radio
spectrum.from.300.kHz.to.3.MHz.
MFCP  Multifunction.Control.Display.Panel
MFD  Multifunction.Display
MFDS  Multifunction.Display.System
MFDU  Multifunction.Display.Unit
MFF  Mixed.Fleet.Flying
MFIT  Mean.Fault.Isolation.Time
MFM  Maintenance.Fault.Memory
MFS  Media.File.Server
MGP  MLS.Glidepath:.A.ground.based.radio.that.
provides.vertical.guidance.during.an.MLS.landing.
MGSCU  Main.Gear.Steering.Control.Unit
MHD  Magnetic.Hard.Drive
MHz  Megahertz.(1,000,000.cycles.per.second)
MIB  Management.Information.Base
MIB II  Management.Information.Base.II
MIC  Microphone..Also.refers.to.the.output.signal.of.the.
microphone.

MicroEARTS  Micro.En.route.Automated.Radar.Tracking. 
System 
MIDO  Manufacturing Inspection District Office 
MIDU  Multipurpose.Interactive.Display.Unit 
MIL  Military 
MIL-HDBK-  General Prediction of Electronic Equipment 
(MTBF) 
MILSPEC  Military Specifications 
MIL-STD-  System Safety Requirements 
Min  (.1.).Minimum.. 
(.2.).Minutes 
MIPS  Million.Instructions.Per.Second 
MIR  Most Important Requirement 
MKP  Multi-function.KeyPad 
MKR  (.1.).Marker.. 
(.2.).Marker.Beacon 
MLA  Maneuver.Limited.Altitude 
MLS  Microwave.Landing.System:.An.ILS.like.system. 
that.potentially.provides.curved.lateral.path. 
selectable.angle.approach. 
MLW  Maximum.Landing.Weight 
MM  (.1.).Mass.Memory..