n. pl. pal·li·ums or pal·li·a (pălē-ə)
1. A cloak or mantle worn by the ancient Greeks and Romans.
2. Ecclesiastical A vestment worn by the pope and conferred by him on archbishops. Also called pall1.
a. The mantle of gray matter forming the cerebral cortex.
b. The mantle of a mollusk or a brachiopod.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.