Simple Definition of toxin

from our Learner's Dictionary

toxin

noun

plural toxins
: a poisonous substance and especially one that is produced by a living thing
the toxin in scorpion venom
Scientists are studying how exposure to environmental toxins [=small amounts of poisons found in air, water, food, etc.] may affect our health.

Cite this Entry

“Toxin.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/toxin. Accessed 18 Jun. 2026.

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