Active ingredient
Active ingredient means any substance (or group of structurally similar substances, if specified by the Agency) that will prevent, destroy, repel or mitigate any pest, or that functions as a plant regulator, desiccant, defoliant, or nitrogen stabilizer, within the meaning of FIFRA sec. 2.
Source
40 CFR § 158.300
Scoping language
The following terms are defined for the purposes of this subpart: