Odds – the likelihood of a team winning, determines the amount of money returned on a bet; see “Oddsmaker”

Oddsmaker – the person in charge of determining a team’s chances of winning 

Offending Team – the team called for committing a foul

Offense – the team with possession of the ball, attempting to score,

Offensive Backfield – the region protected by the “Offensive Line,” or the players who line up in this area

Offensive Holding – grasping a defender to hinder his ability to cover another player or to advance toward the ball, a 10 yard penalty

Offensive Line – a collective term for the five offensive players – the “Center,” two “Tackles,” and two “Guards” – who line p along the line of scrimmage and “Block” defenders to protect the players in the “Backfield”

Offensive Linemen – See “Offensive Line”

Offensive Pass Interference – a 10 yard penalty called on an offensive player for unfairly preventing a defender’s chances of intercepting a pass, or for pushing a covering defender away to gain an advantage in catching a pass

Officials – the referees – a referee, umpire, head linesman, line judge, back judge, field judge, and side judge – dressed in black and white striped uniforms in charge of officiating the game, calling penalties, etc.

Off-Season – the off time between the “Super Bowl” and the first game of the season

Offside – a five-yard penalty called when a defender extends any part of his body into the “Neutral Zone” before the ball is snapped

Off-Tackle – a “Strong Side” running play in which the “Half Back” follows the fullback through the gap between the tackle and the “Tight End”

Onside Kick – if a “Kickoff” travels 10 or more yards, it can be recovered by the kicking team; an onside kick is a short, hard to catch kickoff -- usually employed by the team behind when time is running out – designed to be missed by the “Hands Team” and recovered so the kicking team can retain possession 

Open Up Holes – the primary duty of the “Offensive Line” on a running play, to push the defensive linemen back to create a gap for the “Ball Carrier” to run through

Open Receiver – a “Receiver” who isn’t being covered or who has gotten away from his coverage

Option – a play by the offense that allows the “Quarterback” to choose whether to run, pass, or pitch the ball; unpredictable and hard to defend against, but rarely used in the NFL because of the speed required from the quarterback, and the risk of injury to the quarterback due to the increased amount of tackling and reduced protection he receives in the option formation

Out of Bounds – the area outside of the “Sidelines” and “End Zone” outside of the “Field of Play”

Out of Bounds at Snap – a five yard penalty called when a player enters the field of play after the ball is “Snapped”

Outside – toward the “Sidelines”

Overtime – when the regulation game time ends with a tie score, an extra period of play is added; this period is 15 minutes in the NFL, though the game ends after the first score