pallium

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

• noun A cloak or mantle worn by the ancient Greeks and Romans.
• noun Ecclesiastical A vestment worn by the pope and conferred by him on archbishops.
• noun The mantle of gray matter forming the cerebral cortex.
• noun The mantle of a mollusk or a brachiopod.

from The Century Dictionary.

• noun The cerebral cortex, or that portion of it which forms the roof and sides of the lateral ventricles: this is termed the pallium, or brain mantle, as distinguished from the stem of the brain on which it rests.
• noun In Roman antiquity, a voluminous rectangular mantle for men, corresponding to the Greek himation (see himation), and considered at Rome, because worn by Greek savants, as the particular dress of philosophers; also, a toga or other outer garment; a curtain, etc., of rectangular shape.
• noun Eccles.: In the early church, a large mantle worn by Christian philosophers, ascetics, and monks.
• noun A vestment worn by certain bishops, especially patriarchs and metropolitans.
• noun An alter-cloth; a frontal or pall.
• noun In conchology, the mantle, mantle-flap, or mantle-skirt of a mollusk, an outgrowth of the dorsal body-wall.
• noun In ornithology, the mantle; the stragulum; the back and folded wings together, in any way distinguished, as by color in a gull, etc.
• noun 5. A cirro-stratus cloud when it forms a uniform sheet over the whole sky.

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

• noun (Anc. Costume) A large, square, woolen cloak which enveloped the whole person, worn by the Greeks and by certain Romans. It is the Roman name of a Greek garment.
• noun (R. C. Ch.) A band of white wool, worn on the shoulders, with four purple crosses worked on it; a pall.
• noun The mantle of a bivalve. See Mantle.
• noun The mantle of a bird.

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

• noun A woollen vestment conferred on archbishops by the Pope.
• noun historical A large cloak worn by Greek philosophers and teachers.
• noun zoology The mantle of a mollusc.
• noun meteorology A sheet of cloud covering the whole sky, especially nimbostratus.
• noun anatomy The cerebral cortex.

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

• noun cloak or mantle worn by men in ancient Rome
• noun (Roman Catholic Church) vestment consisting of a band encircling the shoulders with two lappets hanging in front and back
• noun (zoology) a protective layer of epidermis in mollusks or brachiopods that secretes a substance forming the shell
• noun the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum