noun
(countable, organic chemistry) The unsaturated six-membered heterocycle having four carbon atoms, two oxygen atoms, and two double bonds (molecular formula C₄H₄O₂); 1,2-dioxin and 1,4-dioxin.
(countable, organic chemistry) The parent compound dibenzo-1,4-dioxin or dibenzo-p-dioxin (molecular formula C₁₂H₈O₂), in which two benzene rings are connected through two oxygen atoms; dibenzodioxin, oxanthrene.
(countable, organic chemistry) Any of a broad range of toxic or carcinogenic halogenated polycyclic compounds that occur as byproducts of herbicides.