origanum oil

[ə-rĭgə-nəm]
n.
  1. A volatile oil obtained from various species of plants of the genus Origanum, used as a rubefacient, as a constituent in veterinary liniments, and in microscopic techniques.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.