Sidelines cheer is a type of cheering that is done from the sidelines of a sporting event. It involves yelling words of encouragement and support to the players on the field. The two most common words used in sidelines cheer are 'YELL' and 'rah'. YELL is a four-letter word that is used to express enthusiasm and excitement, while rah is a three-letter word that is used to show support and solidarity. Both words are used to motivate the players and create a positive atmosphere for the game.