grey matter noun3 •Literal brains as a general substance.He fell from the 5th floor. There is grey matter on the path behind his head. I'm afraid he's dead. •Brains; a person's ability to think."I'd better be putting my grey matter into that algebra instead of wasting it plotting for a party dress that I certainly can't get." — 1904 •A collection of cell bodies and (usually) dendritic connections, in contrast to white matter.
