A helmet is a form of protective gear worn to protect the head. More specifically, a helmet complements the skull in protecting the human brain. Ceremonial or symbolic helmets (e.g. UK policeman's helmet) without protective functions are sometimes worn. Soldiers wear helmets, often made from lightweight plastic materials.

The word helmet is diminutive from helm, a medieval word for protective combat headgear.[1] The medieval great helm covers the whole head and often is accompanied with camail protecting throat and neck as well. Originally a helmet was a helm which covered the head only partly and protected it from injury in accidents.