n. A substance, usually synthetic although sometimes biological, used to kill or contain the activities of pests
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a chemical used to kill pests (as rodents or insects)
Word Usage
"Though often misunderstood to refer only to insecticides, the term pesticide also applies to herbicides, fungicides, rodenticides, molluscicides and various other substances used to control pests."