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 nickelback is a fifth defensive back who is brought in for particular formations in long passing situations. Nickelback is a not a starting position since the base defensive formations have four defensive backs- two cornerbacks and two safeties. A nickel formation adds on this fifth back, who typically takes the pice of a linebacker, although some teams will choose to use him as a lineman. A defense may choose to use a nickel formation in situations in which the offensive team always uses three or more wide receivers, and where the offense is likely to attempt a forward pass. When looking at a depth chart, the nickelback is the third cornerback. A defense may also use the nickel formation where extra receivers are being subbed into the opposing offense. Defensive formations which add in a sixth cornerback are referred to as dime formations

Nickel Defense – A nickel defense is a defensive scheme that employs five defensive backs instead of the usual four, generally employed in obvious passing situations. The extra defensive back is referred to as a nickelback, and typically replaces one of the linebackers, although some teams will choose to use him as a linesman instead. In modern NFL football, the nickel formation is used with regularity, and a nickelback may expect to see a fair amount of playing time. (This player may also sub in for others.) The nickel defensive scheme is typically used whenever the offense is putting an extra wide receiver into their formation. The defense will also employ this formation in situations in which the opposing offense is likely to attempt a forward pass, such as 3rd-and-long. A dime formation is one that adds in an additional defensive back, with the dimeback serving as the sixth.

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. There are several different variations of this alignment position. In a (most commonly used) 4-3 defensive set, the nose tackle is one of the two defensive tackles in the formation and generally sets on the weak side of the offensive line. In this case, the nose tackle’s job is to serve as a distractor to allow the rush end to be in a one to one matchup with the offense. A second defensive tackle, the under tackle, takes up the strongside guard. Alternatively, teams may employ a 3-4 defensive scheme, in which the nose tackle will serve as the sole defensive tackle, lining up opposite the offense’s center. In this case, the nose tackle will likely serve as the strongside guard, leaving the outside linebackers free to pass-rush.