What does pesticide mean?
A pesticide is a chemical substance or preparation used to kill or control pests, especially insects, weeds, and fungi. The term is most common in agriculture, horticulture, public health, and environmental discussions, where it covers substances applied to crops, gardens, stored food, buildings, or other settings. Its technical definition does not determine whether a pesticide is harmful or beneficial; effects depend on the particular chemical, its concentration, and how it is used. Consequently, discussion of pesticides often involves questions about residue on food, effects on non-target species, groundwater contamination, and the development of resistant pest populations. “Insecticide,” “herbicide,” and “fungicide” are narrower terms for particular kinds of pesticide. Understanding the broader word is useful when evaluating agricultural practices, gardening methods, food regulation, and environmental policy.
A chemical substance or preparation used to destroy or control harmful organisms, especially insects, weeds, or fungi.
"Farmers apply pesticides to reduce crop damage caused by insects and other pests."
The word is also used attributively in compounds such as pesticide use, pesticide residues, and pesticide contamination.
To treat an area, crop, or object with a pesticide in order to destroy or control pests.
"Workers pesticide the greenhouse before planting the seedlings."
This verb form is much less common than the noun and is mainly used in technical or professional contexts.
The plural is standard when referring to multiple chemical agents or pesticide products.
"The study examined the effects of pesticides on pollinators."
The word “pesticide” literally means “pest-killer,” but it now encompasses many chemicals that can affect much more than the intended target.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does pesticide come from?
The word was formed in the early 20th century from “pest” and the combining form “-cide,” meaning “killer.” The suffix comes from Latin caedere, “to kill,” as in related formations such as insecticide, herbicide, and fungicide. “Pest” itself comes through Old French from Latin pestis, referring originally to plague or contagion and later to organisms that damage crops or possessions.
Related word forms
How pesticide is actually used
The term is common in agriculture, environmental science, public health, and food-safety discussions. It can have a neutral technical meaning, but in everyday discussion it may carry concerns about toxicity, environmental effects, or resistance when used repeatedly.
Easily confused with pesticide
A pesticide is a general term for a substance that controls harmful organisms, whereas a herbicide specifically kills or suppresses unwanted plants or weeds.
An insecticide targets insects, while pesticide is the broader term for chemical agents used against pests, including weeds and fungi as well as insects.