also: quarters · quarters coverage
A four-deep shell, and the name for several defenses that share it while behaving completely differently after the snap. Knowing a team plays Cover 4 tells you the shell and very little else.
2 meanings, all below. Jump to the one you heard.
Two corners and two safeties each own a deep quarter, dropping to their area and playing the ball rather than a receiver. Simple to teach and hard to throw deep against, at the cost of open underneath windows and a defender backpedalling at the snap. This is what most coaches picture when they hear Cover 4, and where the distinction has to be drawn the pure version is often called country quarters.
true Cover 4, spot-drop quarters, country quartersmatch quarters, Cover 2The same shell with the deep defenders relating to the receivers in front of them rather than to a landmark. A great deal of modern coaching instruction on quarters means this version, which is why a coach who pictures the zone version and a coordinator who means the matched one can both say Cover 4 and be describing different defenses. See the match quarters entry, where the rules live.
match quarters, pattern-match quartersthe zone version, man coverageThe label is less stable than it looks. Many named analysts write about the whole family and say quarters throughout, never Cover 4. In Nick Saban's terminology Cover 4 is a specific call and the man-match quarters family is Cover 7, so the same two words mean different things in different buildings. Quarters is the safer family label; Cover 4 is a common synonym for it and a specific, different call elsewhere.
The zone version is what gets taught first and is often the whole of what a staff means by quarters at youth and lower high school level. The matched version generally arrives with a coordinator who learned it somewhere else.