4-3 Defense Meaning in American Football

4-3 defense in American football describes a defensive formation with four linemen and three linebackers. Two cornerbacks and two safeties complete the defense. This term matters because roles stay simple and clear. Linemen attack gaps quickly, which helps stop the run. Teams use the 4-3 defense to apply steady pressure and maintain discipline. Linebackers react fast and fill open lanes. Coverage behind them stays consistent. For example, defensive ends rush outside while a linebacker steps into the middle gap.