Man in Motion – an offensive player moving parallel to the “Line of Scrimmage” before the ball is “Snapped”

Man-to-Man Coverage – a defensive pass coverage scheme that requires every “Defensive Back” to cover a specific “Receiver”; as opposed to “Zone Defense”

Middle Guard – the “Down Lineman” positioned directly across from the center, usually one of the largest and strongest defenders because he’s often blocked by both a receiver and one of the “Guards”; also known as the “Nose Guard” or “Nose Tackle”

Midfield – somewhere near the 50 yard line

Motion – refers to the actions of a “Man in Motion”

Mousetrap – See “Trap Block”

Multiple Offense – an offensive scheme that varies formations often in an attempt to puzzle the defense 

National Football League (NFL) – the most well known professional American football association, both in the U.S. and internationally; in the U.S. the NFL comprises 32 teams divided into two “Conferences” and with four “Divisions” in each conference
 
Necessary Line – See “Line to Gain”

Neutral Zone – the length of the ball placed on the “Line of Scrimmage”

NFL Championship – see “Super Bowl”

Nickel Back – a fifth defensive back brought in on long passing situations

Nickel Defense – a defensive scheme that employs five defensive backs instead of the usual four, generally employed in obvious passing situations

Nose Guard – See “Middle Guard”
Nose Tackle – The nose tackle is a defensive alignment position for a defensive lineman. The nose tackle aligns across the line of scrimmage from the offense's center before the play begins.