Gridiron Glossary: 4-3 Under

The 4-3 under is a defensive formation with four defensive lineman, three linebackers and four secondary players where the defensive lineman are shifted away from the strong side.

4-3 under ggj

The name under comes from an under shift.  The opposite is an over-shift toward the strong side.  By moving the 3 technique defensive lineman next to the 5 technique the defense has both the B and C gaps covered.   The defense is better able to defend the point of attack on the weak side since they have shifted their line that way.

Gridiron Glossary is a resource for football terms that are often used by commentators, coaches and players but rarely defined.  If there is a term you have questions about or a definition you don’t agree with, let me know at

About Billy Koehler

Billy Koehler is the founder of and a contributing writer at He has been covering college football since 2006. You can follow him on twitter @billykoehler.
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