What is the name of the NFL's system for reviewing plays?

The NFL's system for reviewing plays is called instant replay.

Instant replay allows officials to use video evidence to check certain on-field rulings, such as whether a pass was complete, whether a runner was down, or whether a player recovered a loose ball in bounds. The referee announces the final decision after the review, either upholding or changing the original ruling.

The NFL first adopted a limited instant replay system in 1986, but discontinued it after the 1991 season. The modern system began in 1999 and included the coach's challenge, signaled by throwing a red flag before the next play begins. Coaches receive a limited number of challenges and risk losing a timeout when a challenge fails.

Coach's challenge is therefore related to instant replay but is not the name of the entire system. Some reviews are initiated automatically by replay officials, including certain scoring plays and turnovers, so not every review depends on a coach's request.