In American football, an signal is when the QB, just before the snap of the play, changes the pre-determined play at the line of scrimmage. Essentially, it's a last-minute adjustment! The QB might notice something on https://t-l-ko-nh-ci-5435724.boyblogguide.com/40724423/a-defines-an-play-call-in-the-nfl-a-simple-guide