n., pl., -mas, or -ma·ta (-mə-tə).
A usually benign tumor of the adrenal medulla or the sympathetic nervous system in which the affected cells secrete increased amounts of epinephrine or norepinephrine.
[pheochromocyte, chromaffin cell (Greek phaios, dusky + CHROMO- + -CYTE) + -OMA.]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
