What color card indicates a caution issued by the referee?

The yellow card is universally recognized in soccer as the signal for a caution issued by the referee. When a player receives a yellow card, it serves as a warning for misconduct, such as unsporting behavior, dissent, or repeated fouls. This important signaling helps maintain discipline during the match.

In contrast, a red card indicates a more severe sanction, leading to the player's dismissal from the game. Other colors, such as green or blue, do not convey specific penalties within the standard Laws of the Game. Thus, the yellow card serves a vital role in managing the conduct of players and ensuring that the game is played fairly.