helmet Meaning, Definition & Usage

  1. noun armor plate that protects the head
  2. noun a protective headgear made of hard material to resist blows

WordNet

Hel"met noun
Etymology
OF. helmet, a dim of helme, F. heaume; of Teutonic origin; cf. G. helm, akin to AS. & OS. helm, D. helm, helmet, Icel. hjalmr, Sw. hjelm, Dan. hielm, Goth. hilms; and prob. from the root of AS. helan to hide, to hele; cf. also Lith. szalmas, Russ. shleme, Skr. çarman protection. Cf. Hele, Hell, Helm a helmet.
Definitions
  1. (Armor) A defensive covering for the head. See Casque, Headpiece, Morion, Sallet, and Illust. of Beaver.
  2. (Her.) The representation of a helmet over shields or coats of arms, denoting gradations of rank by modifications of form.
  3. 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.
  4. That which resembles a helmet in form, position, etc.; as: (a) (Chem.) The upper part of a retort. Boyle. (b) (Bot.) The hood-formed upper sepal or petal of some flowers, as of the monkshood or the snapdragon. (c) (Zoöl.) A naked shield or protuberance on the top or fore part of the head of a bird.

Webster 1913