castoreum

\Cas*to"re*um\, n. [L. See Castor.] A peculiar bitter orange-brown substance, with strong, penetrating odor, found in two sacs between the anus and external genitals of the beaver; castor; -- used in medicine as an antispasmodic, and by perfumers.
Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.

castoreum

a bitter strong-smelling creamy orange-brown substance that consists of the dried perineal glands of the beaver and their secretion

Source: The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

 

castoreum

the musky oil the beaver uses to grease its coat and mark scent mounds to delineate its territory

Source: From chapter 2, "Nature's Hydrologists" in Water: a natural history  by Alice Outwater.
Copyright  1996 by Alice Outwater.
Published by www.shawsheen.org/Beavers/Natural_History_of_Beavers/natural_history_of_beavers.html. All rights reserved.