MCM

Measurements

Thousand circular mils or kcmil, the wire gauge is equivalent cross sectional area (500 MCM = 500,000 circular mils)
Million cubic metre, the unit of volume

Magic Circle Music, a heavy metal record label
Magic City Misfits, a roller derby team from Jacksonville, FL
Maverick City Music, a contemporary christian group
MCM (TV channel), a French music channel
Music City Mystique, a Percussion Independent World (PIW) Drumline
The Mad Capsule Markets, a Japanese punk-metal band
MCM – The Gospel: The Missing Gems of MCM Caveman (1994-2011) (Mark Layman), rapper and former frontman for UK hip-hop group Caveman
MCM Records, a French record label established by Jacques and Marcelle Morgantini

Medical countermeasure (MCM), products that can protect from the effects of a chemical, biological, or nuclear attack
Minichromosome maintenance protein, which forms DNA helicase in eukaryotic species
Mobil Composition of Matter or Mobil Crystalline Material, a family of porous silicate-based materials
Macrocephaly-capillary malformation (M-CM), a rare genetic syndrome
Methylmalonyl-coenzyme A mutase, an enzyme
the Monte Carlo method

MCM pistol, a 25-meter Standard Pistol
Mine Counter-measures, defensive techniques against military mines
Manual for Courts-Martial, the official guide to the conduct of courts-martial in the United States
Marine Corps Marathon, a 26-mile marathon held in Arlington, VA and Washington, DC
A US Navy hull classification symbol: Mine countermeasures ship (MCM)

Micro Computer Machines, an early manufacturer of microcomputers, such as the MCM/70
Microsoft Certified Master
Mobile content management, software capable of storing and delivering content to mobile devices
Multi Carrier Modulation
Multi-chip module, a specialized electronic package

Monaco Heliport's IATA code
PABCO Transit, Inc or Morris County Metro, a bus system formerly serving Morris County, New Jersey

Maranatha Campus Ministries, a former Christian ministry in the U.S.
Mathematical Contest in Modeling, challenges teams of students to clarify, analyze, and propose solutions to open-ended problems
M-C-M', Money-Commodity-Money, one of the forms of commodity trade in the theory of Karl Marx
MCM London Comic Con, a multi-genre fan convention held in London
MCM Worldwide, leather luxury goods brand
Melbourne City Mission, a charity in Australia
Mid-Century modern, an architectural, interior and product design form
Mighty Car Mods, a YouTube show about modifying cars
Roman numeral for 1900
Montreal Citizens' Movement, a municipal political party in Montreal, Quebec, Canada