Meaning of brown fat

brown' fat'

Pronunciation: [key]
  1. brownish-yellow adipose tissue in the upper back, or interscapular, region of many mammals, most conspicuously in hibernating species, composed of numerous innervated fat cells that can produce heat during cold stress; thermogenic tissue.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.