Test system
Test system means any animal, plant, microorganism, chemical or physical matrix, including but not limited to, soil or water, or components thereof, to which the test, control, or reference substance is administered or added for study. Test system also includes appropriate groups or components of the system not treated with the test, control, or reference substance.
Source
40 CFR § 792.3
Scoping language
As used in this part the following terms shall have the meanings specified: