Also found in: Medical.


Either of two viscous liquid esters, C20H28O3 or C21H28O5, occurring naturally in pyrethrum plants and used as insecticides.

[New Latin ciner(ariifolium), specific epithet of Tanacetum cinerariifolium, the species of pyrethrum from which the esters were originally derived (Latin cinerārius, of or for ashes (in reference to the cinereous leaves), from cinis, ciner-, ashes + folium, leaf) + -in.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Elements & Compounds) either of two similar organic compounds found in pyrethrum and used as insecticides. Formulas: C20H28O3 (cinerin I), C21H28O5 (cinerin II)
[C20: from Latin ciner-, cinis ashes + -in]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014