My pleasure Janet. The referee shows the yellow card in European football when a player fouls another player. If the foul is serious a red card is shown and the player must leave the football field at once that means that one of the two teams are playing one man short it sounds complicated but it is in fact easy to understand when one watches a football match being played. Also a much used term off the football field. Have a good day now with thanks and love bern.......Peace