MC - M/C - Motorcycle Club, referring to the tightly knit brotherhoods of biker gangs.

Mad Max - A circular burnout made by spinning the rear tire and then rotating the bike 360 degrees with the locked front wheel as the axis. Bonus for crossing the circle with a straight rubber mark when finished.

Mama - A woman who is available to all Biker Gang members

MANF - Multi Adjustable Nut F**ker, aka adjustable spanner! (UK). A wrench that messes up any bolt or nut it is applied to.

Market Street Commandos - An early Motorcycle Gang

Marquis deSaddle - A highly uncomfortable motorcycle seat

Masey Fergason/JCB/Tracker - Harley-Davidson

Mattress Cover or Ground Cover - Young Woman

Mechanic - Wrench

Megaphone - Goes onto the end of the exhaust to help tune it

Mexican Socket Set - Crescent wrench

Mill - Engine

Milwaukee Vibrator - A Harley-Davidson

Minger - Wheelie

MMI - Motorcycle Mechanics Institute.

Money Burner - Anyone who rides a Harley-Davidson

Monkey Butt - What you get after riding your dirt bike all day

Mono - Wheelie

Motorcycle Jockeys - Anyone who rides any motorcycle.

MSF - Motorcycle Safety Foundation (Training). The highly recommended way to learn how to properly and safely ride a motorcycle. Offered in many countries around the world for a very reasonable price.

Mud Puppies - ATV and ATC folks

Mushrooms or Crash Bungs - terms for the plastic 'bungs' you attach to the frame to protect the fairing etc in case of a 'spill' or crash.