Attention-deficit hyperactivity disorder (ADHD), (formerly termed minimal cerebral dysfunction, MCD)

The Main Cabin Door, on an aircraft.

MCD, Major Compulsive Disorder, someone that is not quite an Obssesive but far past minor, term coined by Sandy N. Nguyen - San Francisco, California

Mind control device

Bovine spongiform encephalopathy (commonly known as Mad Cow Disease, MCD)

mCD, Minor Compulsive Disorder, someone that is not quite an Obssesive, term coined by Sharon Nguyen - Honolulu, Hawaii

Male chastity device

mini compact disc, a discographical release containing fewer songs than an EP (MCD)

Maxi single Compact Disc

Murder City Devils

Municipal Corporation of Delhi

Minimal Change Disease

Melbourne College of Divinity

MCD PRODUCTIONS, an Ireland-based event promoter.

Minor civil division, a geographical term used by the United States Census Bureau

Magnetic circular dichroism, an effect studied in physics.

In British archaeology, the Monument Class Descriptions produced by English Heritage

Masters of Communication Disorders, a college degree generally regarding Communication disorders, including specifically the fields of Audiology and Speech and language pathology.

McDonald's (stock symbol MCD)

millicandela (mcd)

Mesoscale discussion (MCD), forecast issued by the Storm Prediction Center

The Missile Countermeasure Device, an anti-ATGM device mounted on M1A1 Abrams tanks.

Michael Clarke Duncan, African-American actor

1400 in Roman numerals.

Merced (Amtrak station), California

the IATA airport code of the Mackinac Island Airport in Michigan

NYSE: MCD, the stock symbol of McDonald's Corporation, the world's largest chain of fast-food restaurants.

mcd is an abbreviation for millicandela, an SI unit of luminous intensity.