Colloquial (short) name of a toxic by-product (and sometimes contaminant) of herbicides;
the full name of this species is: 2,3,7,8-tetrachlorodibenzo[
b,e][1,4]-dioxin.
Source:
PAC, 1990, 62, 2167
(Glossary of atmospheric chemistry terms (Recommendations 1990))
on page 2185