toxin (n.)

1660s, from French toxique and directly from Late Latin toxicus "poisoned," from Latin toxicum "poison," from Greek toxikon (pharmakon) "(poison) for use on arrows," from toxikon, neuter of toxikos "pertaining to arrows or archery," and thus to a bow, from toxon "bow," which has been regarded as a loan-word from Scythian. Watkins suggests a possible source in Iranian taxša- "bow," from PIE *tekw- "to run, flee." Beekes, pointing to the early attestation of the Greek word, suggests a Pre-Greek origin.

As a noun from 1890. Toxic waste is by 1888 in medicine, "toxin;" by 1955 as "chemical or radioactive waste."

"substance neutralizing poisons," 1892; see anti- "against" + toxin. Coined in 1890 by German bacteriologist Emil von Behring (1854-1917). Antitoxic "substance which counteracts a poison" is from 1860 in English.

word-forming element in chemistry, usually indicating a neutral substance, antibiotic, vitamin, or hormone; a modification and specialized use of -ine (2).