n. A defensive cover for the head.n. () In present use, a stiff military hat of domed or pointed form, sometimes of metal or stiffened with bars of metal so as to afford defense against a sword-cut.n. A hat, usually of leather and having a vizor and broad neckguard, worn by firemen.n. A hat of similar form worn by policemen, or by civilians for any purpose, especially in not climates. Such hats are usually of felt or pith, so formed as to have space for ventilation around the head or openings for ventilation above.n. The headpiece of a suit of submarine armor. It is usually formed of sheetmetal and leather, and is fitted over the head and shoulders. It is provided with thick glass windows for the eyes and with pipes for air. See submarine, armor, under armor.n. A havelock used by anglers, with a projection in front of the face that can be covered by a netting or veil as a protection against insects.n. In heraldry, the representation of a helmet, set above the escutcheon and seeming to support the armorial crest. Distinctions of rank are indicated by the metal, the number of bars in the vizor, and the position.n. Same as helmn. In botany, same as galea, 1 .n. The upper part of a retort.n. In entomology, the galea of an insect's maxilla.n. plural A breed of small, fancy pigeons which have a white body and the tail and top of head black or red. The name is given in allusion to this cap or helmet.