- any of various forms of protective head covering worn by soldiers, firefighters, divers, cyclists, etc.
- medieval armor for the head.
- (in fencing, singlestick, etc.) a protective device for the head and face consisting of reinforced wire mesh.
- anything resembling a helmet in form or position.
- a piece of protective or defensive armour for the head worn by soldiers, policemen, firemen, divers, etc
- biology a part or structure resembling a helmet, esp the upper part of the calyx of certain flowers
mid-15c., perhaps a diminutive of Old English helm “protection, covering; crown, helmet” (see helm (n.2)). But Barnhart says from Middle French helmet (Modern French heaume), diminutive of helme “helmet,” from the same Germanic source as helm (n.2). “Middle English Dictionary” points to both without making a choice. “Old English helm never became an active term in the standard vocabulary of English.” [Barnhart]