Mars Global Surveyor 
Mobile Gun System 
Missile Guidance Set 
Media Gateways 
Mission Ground Station 
Mobile Ground Station 
Mobile Ground System 
Maine Geological Survey 
Malaysian Government Securities 
Maryland Geological Survey 
McMurdo Ground Station 
Minnesota Geological Survey 
missile guidance system 
Aeromagar 
Machine Gun System 
Machine Guns 
magnetic guidance system 
malignancy grading system 
malignant gliomas 
Mammalian Genotyping Service 
mammary gland secretions 
Manchester Grammar School 
Map Generation System 
Maritime Geoscience Services 
Master Gunnery Sergeant 
Master of General Studies 
maternal grandsire 
Meckel-Gruber syndrome 
memory-guided saccade 
Merit Global Service