Real Dictionary

dioxin
variable noun: Dioxins are poisonous chemicals which occur as a by-product of the manufacture of certain weedkillers and disinfectants.

dioxin in American English
any of a family of heterocyclic hydrocarbons; esp., any of a number of isomers of a highly toxic chlorinated teratogen, TCDD, that occurs as an impurity in some herbicides and defoliants, including trichlorophenoxyacetic acid, a component of Agent Orange
noun: a general name for a family of chlorinated hydrocarbons, C12H4Cl4 O2, typically used to refer to one isomer, TCDD, a by-product of pesticide manufacture: a toxic compound that is carcinogenic and teratogenic in certain animals

dioxin in British English
noun: any of a number of mostly poisonous chemical by-products of the manufacture of certain herbicides and bactericides, esp the extremely toxic 2,3,7,8-tetrachlorodibenzo-para-dioxin

dioxin in Chemical Engineering
noun: A dioxin is a chemical product, usually a poisonous one, which is produced when some herbicides and bactericides (= substances which destroy bacteria) are made.