Dioxin

n. poisonous substance which is used in the manufacture of various chemical products

Dioxin in its original usage denoted the organochemical heterocyclic compound with the general chemical formula C4H4O2 in which two CH groups of a benzene ring were replaced (endocyclic substitution) by oxygen atoms, of which two isomers were possible, the ortho (o) and the para (p) variety: 1,2-dioxin and 1,4-dioxin. This name then extended to the family of compounds derivable from the parent compounds by exocyclic substitution, and especially to the dibenzo substitution of the para variety.
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Noun
1. any of several toxic or carcinogenic hydrocarbons that occur as impurities in herbicides
(hypernym) hydrocarbon
(substance-holonym) Agent Orange

n. dioxin, poisonous substance which is used in the manufacture of various chemical products

Any of a family of compounds known chemically as dibenzo-p-dioxins. Concern about them arises from their potential toxicity as contaminants in commercial products. Tests on laboratory animals indicate that it is one of the more toxic anthropogenic (man-made) compounds.