The following nicknames are given to a unit (defensive, offensive and special teams) or a secondary nickname given to some teams used to describe a style of play or attitude of teams at times in accordance with phrases in popular culture of the time. They are not the official franchise nicknames of the National Football League (NFL). Since the NFL's inception in 1920, players, coaches, team executives, league officials, and football games have been given nicknames based on either individual achievements, team achievements, historical events, etc.