, a warning given out by the referee
to a player for a clearly dangerous or intentionally extra-legal
play. The player's name and number are written in the game book
by the referee (hence the phrase "being booked
"), and an approximately 3" x 4" yellow
plastic card is displayed above the referee's head, with the referee facing in the direction of the player being carded.
A player may continue playing after receiving one yellow card; a second yellow card within a single match invokes an automatic red card, meaning ejection. In some leagues, an accumulation of a certain number of yellow cards over a given number of matches can result in suspension for future matches, even if no red was received in any particular match.