A balaclava is a combination head and neck covering that provides a great deal of warmth. One most commonly sees them on skiers or worn as a part of military outfitting to reduce the wearer’s visibility to others. To US English speakers, the term is not very common, and one would traditionally see the term ski mask used instead.
The common balaclava is typically made of wool, though some may also be made of acrylic, cotton, or fleece. The item covers the head, ears and neck, but has an opening for the eyes. Usually, it also includes a tiny opening near the nostrils for easier breathing. The hat/scarf combo can just become a hat by rolling up the scarf portion in many models. If the neck or chin becomes too warm, the headgear can be easily converted.
The name comes from the town of Balaklava, Crimea. During the Crimean War of 1854-1856, many British troops were unused to the extremely cold winter conditions. People from the town sent these hand knitted “ski masks” to help provide extra warmth for the British soldiers.
One often sees balaclavas worn in outdoor winter sports. Those made of black silk might be most associated with ninjas, and any modern ninja costume tends to include a portion that covers the face. Sadly, the garment is also associated with terrorists and criminals, who wish anonymity while committing illegal acts.
Frequently, competitive auto racers use a flame retardant balaclava underneath their helmets. This is thought to protect the face should a race car accidentally catch fire. In addition, it allows some filtration of smoke by shielding the mouth, providing the driver with slightly more time for rescuers to reach him or her.