Newer fans often hear “slant”, “post” or “out” and assume the play is built around one receiver. NFL passing games are usually better understood as combinations.

Individual routes

A slant breaks quickly inside. An out breaks toward the sideline. A post attacks inside and deep. A corner route breaks outside and deep. A go route pushes vertically.

The concept is the important part

A coach combines routes so one defender cannot comfortably cover both. One route may clear space while another enters the space that was vacated.

ConceptBasic ideaWhat it stresses
SmashShort outside route underneath a corner route.A Cover 2 corner/safety relationship.
MeshTwo shallow crossing routes.Man coverage and traffic underneath.
FloodThree routes attack one side at different depths.Zone defenders who must cover multiple levels.
Four VerticalsFour receivers push vertically.Deep zone spacing and safety rules.

Why motion helps

Motion can change the defensive leverage before the concept even begins. It can reveal man coverage, create a free release or force defenders to communicate just before the snap.

Best way to watch: don't ask only “who caught it?” Ask which defender the concept was trying to put in conflict.