Meaning

noun the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum

noun (zoology) a protective layer of epidermis in mollusks or brachiopods that secretes a substance forming the shell

noun (Roman Catholic Church) vestment consisting of a band encircling the shoulders with two lappets hanging in front and back

originBorrowed from Latin pallium (“a cloak”). Doublet of pall.

Etymology from Wiktionary, CC BY-SA 3.0