Chemical substance and Pesticide

Chemical substance noun - Material produced by or used in a reaction involving changes in atoms or molecules.

Pesticide and chemical substance are semantically related. In some cases you can replace term "Pesticide" with "Chemical substance", this terms are similar.

Pesticide noun - A chemical used to kill pests (as rodents or insects).

Chemical substance and pesticide are semantically related. Sometimes you can use "Chemical substance" instead a noun "Pesticide".