Definition of helmet

• n. - A defensive covering for the head. See Casque, Headpiece, Morion, Sallet, and Illust. of Beaver.
• n. - The representation of a helmet over shields or coats of arms, denoting gradations of rank by modifications of form.
• n. - A helmet-shaped hat, made of cork, felt, metal, or other suitable material, worn as part of the uniform of soldiers, firemen, etc., also worn in hot countries as a protection from the heat of the sun.
• n. - That which resembles a helmet in form, position, etc.
• n. - The upper part of a retort.
• n. - The hood-formed upper sepal or petal of some flowers, as of the monkshood or the snapdragon.
• n. - A naked shield or protuberance on the top or fore part of the head of a bird.