The individuals responsible for enforcing the rules of the game during play. There are seven officials in a normal staff for a football game: the referee, umpire, head linesman, line judge, side judge, back judge, and field judge. Each official has a specific set of responsibilities and a specific position on the field. The referee is considered the head of the team and announces all calls.
The officials are responsible for enforcing all rules throughout play. They do so by announcing penalties by throwing a flag and reporting to the head official, or referee, about the infraction committed. The officials are notable for their black and white striped uniforms, which sometimes get them the designation of "zebras". The officials have to interpret plays as they occur, and each official needs to keep track of a certain aspect of the game. Certain official calls can be overturned by instant replay.