(UK, uncountable) The invasive plant Impatiens glandulifera. / Used other than figuratively or idiomatically: see policeman, helmet.

A species of friarbird, Philemon buceroides, of eastern Indonesia, New Guinea, and northern Australia.

plural of helmeted friarbird

(historical) A bronze helmet of Ancient Greek origin, covering the head and neck, with slits for the eyes and mouth.

A leather head covering with earflaps used by early aviators.

A balaclava (type of headgear).

A mining helmet, a hard hat worn by miners that usually carries a light on the front. / Eggcorn of pith helmet.

(military, slang) A style of soldier's helmet that looks the same or similar to the helmet used by the British Empire, Commonwealth and U.S. soldiery during World War I.

(idiomatic) An accidental messy hairdo resulting from the wearing of a helmet.

plural of helmet hair