The U.S. Armys standard carbine, fires 5.56mm NATO round, shares 75-80% of the parts used in the M-16. For some reason ten year olds think they are qualifyed to operate and clean one because they use it in video games, and they read the wikipedia page on it.
If you look at most stock footage of the war on terror it will have an M4 in view.
by Burkus December 6, 2008
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The main west bound road out of London England. It connects the capital with Bristol and the Welsh Cities of Newport, Cardiff and Swansea. Renowned for it's traffic congestion. Particulary around Bristol where it intesects the M5
...and again traffic is moving slowly on the M4, drivers are advised to seek an alternative route.
by black flag June 15, 2004
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New kids at the school, first years, naive young student that U4s and above may laugh at and bully for their entire first year before they are accepted into the college.

Bottom of the school heirachy, annoying M4s should be bullied in boys case and bitched about in girls houses, until they are properly behaved.

Sucking up to/ making friends with M4s is forbidden in their first weeks at school.
Wow the M4s this year are arrogant, as always.
by EpsomBanter August 29, 2010
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An extremely powerful assault rifle used by special forces and the U.S. military; it uses the 5.56 mm round. An M203 (grenade launcher) can be attached under its short barrel to cause maximum damage and doom. It is black with pink polka-dots and a lot of naked lumberjacks use them. Lumberjack slams are also delicious. They are eggs, ham, bacon, sausage, pancakes, and parsley. They taste slammingly tasty.
That stupid asshole was running down the hill when he tripped on a rock and the M4 Assualt Rifle he was carrying went off and shot a mailman.
by Borg November 28, 2004
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Sandrine Tien
Yvonne Ho
Pauline Do
Tiffinie Pham
M4 is awesome.
by Alan Setthaboupha May 4, 2004
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1. A modular carbine used by police and military forces worldwide.

2. The cliche weapon of choice in first-person shooters.

3. The reason every prepubescent male in America thinks they know how guns work and how to correctly and accurately operate such weaponry.
1. The M4 derived from the CAR-15, an upgrade from the A1's used in much of the fighting in Vietnam.

2. Bob picked the M4 when he was playing Rainbow Six.

Prepubescent male 1: dude we knoe everything about guns from playing video games
Prepubescent male 2: the m4 is a 5.56 NATO caliber carbine used by special forces and SWAT teams, it features an integral flash supressor with a fully modular design base including the rail interace system, a collapsable stock, backup ironsights, and room for a mounted foregrip, 40mm m203 grenade launcher, flashlight, laser sight, and a nifty carrying handle!
Prepubescent male 3: dude we should join the special forces were so good
by inbe July 27, 2005
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A 5.56mm (.223 Remington) assault rifle developed by Colt's Mfg. as a carbine version of the company's M16A2 assault rifle
The SWAT team's armory was filled with M4 Carbines
by JoeBob July 29, 2003
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