(redirected from pyrethrin II)
Also found in: Medical, Encyclopedia.


 (pī-rē′thrĭn, -rĕth′rĭn)
Either of two viscous liquid esters, C21H28O3 or C22H28O5, that are extracted from pyrethrum flowers and used as insecticides.

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.


1. (Elements & Compounds) Also called: pyrethrin I an oily water-insoluble compound used as an insecticide. Formula: C21H28O3
2. (Elements & Compounds) Also called: pyrethrin II a compound of similar chemical structure and action, also found in pyrethrum. Formula: C22H28O5
[C19: from pyrethrum + -in]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(paɪˈri θrɪn, -ˈrɛθ rɪn)

either of two chemicals, C21H28O3 or C22H28O5, extracted from pyrethrum flowers: used as an insecticide.
[1830–40; pyrethr (um) + -in1]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.


n piretrina
English-Spanish/Spanish-English Medical Dictionary Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
Mentioned in ?
References in periodicals archive ?
Pyrethrum extract (25% pyrethrin I and pyrethrin II) was purchased from Fluka Chemie (Buchs, Switzerland).