-ˈpirəfäs, -ˈpīr- noun
( -es )
Etymology: chlor- + pyri d- + -fos , alteration of -phos (as in coumaphos — herein)
: a toxic crystalline organophosphate pesticide C 9 H 11 Cl 3 NO 3 PS that inhibits acetylcholinesterase and is used to control insect pests and ticks