A term for the particular combination of players a team uses on a certain play. An offense will adjust the number of linemen, receivers and backs that they use depending on the situation, while the defense will respond with different combinations of linemen, linebackers and ends. The package that a team substitutes before a play will be an indicator of the types of plays that it is likely to run.
Teams will change the package based on the down and distance, as well as the general game situation. For example, an offense that has only a yard to go for a first down or a touchdown may put in a "jumbo" package that has larger players and more blockers, knowing that they have a good chance to pound the ball for a yard. The other extreme is that a team that has to throw the ball a lot may put in four or five wide receivers. Defenses will respond to the offensive packages with their own alignments. A team that is facing a lot of receivers may go to a "nickel" or "dime" package, which means they take linemen or linebackers off of the field and replace them with extra defensive backs to play pass defense.