galea

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A helmet-shaped part, such as the upper petal of certain plants or part of the maxilla of an insect.

from The Century Dictionary.

• noun A helmet, or something resembling a helmet in shape or position.
• noun [capitalized] In zoology, a genus of fossil sea-urchins or echini of galeate form.
• noun In entomology, an appendage of the stipes of the maxilla of some insects, as distinguished from the lacinia, another appendage of the same gnathite. Thus, in the cockroach the galea is soft, rounded, and possibly sensory in function, while the lacinia is a hard curved blade, serrate and spinose. See lacinia. The extremity of the maxillæ is often terminated by two divisions or lobes, of which the outer, in the Orthoptera, is termed the galea. In Cuvier's Règne Anim. (tr. of 1849), p. 474.
• noun In ornithology, a frontal shield, as that of a coot or gallinule; a horny casque upon the head, as that of the cassowary (see cut under cassowary); a great helmet-like boss upon the bill, as in the hornbill. See cut under hornbill.
• noun In anatomy: The amnion; especially, the part of the amnion which may cover the head of a new-born infant like a cowl. Also called caul. The galea capitis (which see, below).
• noun In botany, a name given to the parts of the calyx or corolla when they assume the form of a helmet, as the upper lip of a ringent corolla.
• noun In pathology, headache extending all over the head.
• noun In surgery, a bandage for the head.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) The upper lip or helmet-shaped part of a labiate flower.
• noun (Surg.) A kind of bandage for the head.
• noun (Pathol.) Headache extending all over the head.
• noun (Paleon.) A genus of fossil echini, having a vaulted, helmet-shaped shell.
• noun (Zoöl.) The anterior, outer process of the second joint of the maxillae in certain insects.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a Roman helmet
• noun botany an organ or a part of a plant that is shaped like a galea (helmet)
• noun entomology a mouthpart found in some species of chewing insect, which is shaped like a galea (helmet)
• noun surgery A kind of bandage for the head.
• noun medicine A headache extending all over the head.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an organ shaped like a helmet; usually a vaulted and enlarged petal as in Aconitum