The story
From dichlor(o)v(inyl) + -fos (“phosphorous derivative”).
Etymology from Wiktionary, CC BY-SA 4.0.
dichlorvos
Today it means: A highly volatile organophosphate, 2,2-dichlorovinyl dimethyl phosphate (DDVP), widely used as a fumigant to control household pests and to protect stored product from insects. Full definition →