Home › Words › I › insecticideinsecticide/ɪnˈsɛk.tɪˌsaɪd/insecticide means any of various substances used to kill insects.insecticide is pronounced /ɪnˈsɛk.tɪˌsaɪd/.EtymologyFrom French insecticide, as insect + -icide.nounAny of various substances used to kill insects.e.g.“The dried seed powder of custard apple (Annona squamosa L; family: Annonaceae) has been used as an insecticide in India and many other tropical countries since ancient times.” — 2009, Handbook of Pesticides: Methods of Pesticide Residues Analysis, →ISBN:Definitions & examples from Wiktionary (CC BY-SA 3.0).