A mask is an artifact that covers or conceals any part of the face. They can be worn for a wide range of reasons.
- Protection (more under practical) - Masks can be used to protect the wearer from things ranging from gunfire (as in the head masks worn by the SWAT team) to gas masks, which protected the wearer from biological and chemical attacks.
- Performance - In many theatre groups, masks are used for dramatic effect or as a way to add emotion to a performance.
- Amusement/costumes - Masks can be worn for personal amusement or to impersonate another person or character. Perhaps the most well known display of this is Halloween
- Balls - Masquerade balls are either formal or semi-formal events attended by people wearing masks. The masquerade ball tradition started in France, and has spread in popularity to almost every Western nation, including the United States.
- Ceremonies - Within African and ancient American (both North and South) societies, there were many rituals that involved masks. In the ancient religions (some of which still exist today) masks were believed to heighten the atonement one had with a Deity,
- Practical purposes - In the modern era, masks are used practically for a wide range of reasons.
Medical masks, such as oxygen masks, are generally used as a way to treat medical conditions or prevent the spreading of diseases. The masks worn by surgeons protect the patient just as much as they protect the doctor. While an oxygen mask does not provide protection per se, it does allow a patient with a lung problem, such as emphysema to lead a normal life.
There are also masks that are specifically designed for the protection of the wearer. A football player wears a mask to protect himself from impacting other players and to keep stray hands out of his eyes, while a firefighter wears a flip-down mask to keep embers out of the eyes whilst fighting a fire.