TOXIN
toxin
(noun) a poisonous substance produced during the metabolism and growth of certain microorganisms and some higher plant and animal species
Source: WordNet® 3.1
Etymology
Noun
toxin (plural toxins)
A toxic or poisonous substance produced by the biological processes of biological organisms.
Usage notes
Toxin is often incorrectly used to describe various toxic substances in a body that need to be removed. The correct term to use in this case is toxicant.
Source: Wiktionary
Tox"in, Tox"ine, n. Etym: [Gr.Toxic. ]
Definition: A poisonous product formed by pathogenic bacteria, as a toxic
proteid or poisonous ptomaine.
Source: Webster’s Unabridged Dictionary 1913 Edition