A route is a pattern or path that a receiver in gridiron football runs to get open for a forward pass. Routes are usually run by wide receivers, running backs and tight ends, but other positions can act as a receiver given the play.
One popular way to organize routes is with a "route tree". A route tree is a way to show all the various routes with one diagram.
Routes
Curl
A curl route, also called a hitch or hook (sometimes a button hook), is the receiver appears to be running a fly pattern but after a set number of steps or yards will quickly stop and turn around, looking for a pass. This generally works best when the defending corner or safety commits himself to guarding the fly and is unable to stop quickly enough to defend the pass. A "curl out" on the sideline is often referred to as a comeback route.
The curl is a pattern used frequently by the West Coast offensive scheme, where quick and accurate passes are favored.
This route can also be used in what is called a screen, where while the receiver is receiving the pass, one or more linemen, tight ends, or running backs will run in the direction of the receiver in order to block the initial pursuing defenders so that the receiver has time and space to be able to run after the catch.
Drag
A drag route (also known as an in route or a dig route) is a route run by a receiver, where the receiver runs a few yards downfield, then turns 90° towards the center of the field and runs parallel to the line of scrimmage. This type of route is relatively safe and is thrown to an agile receiver who can make a play after the catch. Alternatively, a drag route may be used as a second option if the principal receiver on a play is covered.
The use of two crossing drag routes can also be used to try to create an open receiver by using the other receiver to block the path of a defensive back in a man coverage scheme. Out and in routes are the most difficult routes to cover in man-to-man coverage, but can be dangerous plays to run because, if the defender intercepts the pass, he will often have a clear path to the end zone.
Corner
A corner route is a pattern run by a receiver, where the receiver runs up the field and then turns at approximately a 45-degree angle, heading away from the quarterback towards the sideline. Usually, the pass is used when the defensive back is playing towards the inside shoulder of the receiver, thus creating a one on one vertical matchup. The corner route is less likely to be intercepted when compared to the slant route, because it is thrown away from the middle of the field. The pass is used frequently in the West Coast offensive scheme, where quick, accurate throwing is key. The pass may also be used closer to the goal line in what is called a "fade". The quarterback will lob the ball over a beaten defender to a wide receiver at the back corner of the end zone.
Fly
A fly route, also called a streak route or go route, is a pattern run where the receiver runs straight upfield towards the endzone. The goal of the pattern is to outrun any defensive backs and get behind them, catching an undefended pass while running untouched for a touchdown. Generally, the fastest receiver on the team or any receiver faster than the man covering him would be the one to run these routes. When run down the sidelines, a fly can be called a fade route.
Fly patterns can also be used to clear out space for other receivers. Generally, a fly pattern will draw the attention of both the cornerback assigned to the receiver as well as "over the top" help from a safety. This can create a large gap in coverage, allowing another receiver to run a shorter route, but then gain many yards after the catch because the safety committed to the deep receiver.
The famed "Hail Mary" play generally involves between three and five receivers all running fly routes in order to have the most chance of one of them catching the ball and scoring or at least gaining significant yardage.
Out
An out route (or down and out or jet route) is a pattern run by a receiver. On an out route, the receiver will start running a fly pattern (i.e., running straight down the field toward the end zone) but, after a certain number of steps, will cut hard 90 degrees "to the outside", or toward the sideline, away from the quarterback. If the cut comes very quickly, usually after only a few steps, it is called a "quick out". Out routes generally allow a one-on-one match-up between the receiver and the defensive back who is guarding him, as safeties generally are concerned with helping out on long routes downfield or the center of the field.