Webster’s New World College Dictionary, Fourth Edition, compiled by the
editors of Webster’s New World Dictionaries. Copyright © 2010 by Houghton
Mifflin Harcourt. Published by Houghton Mifflin Harcourt. All rights reserved.
Word origin of 'pyrexia'ModL < Gr pyrexis, feverishness < pyressein, to be feverish < pyretos: see pyretic