1. The act of applying a gas or smoke to disinfect or to purify something: Fumigation was necessary in order to eliminate the bed bugs that were infecting Lynn's home.
2. Etymology: "to make aromatic smoke as part of a ceremony" from Old French fumigation, from Latin fumigationem, fumigatio, from fumigare, "to smoke"; from fumus, "smoke, fume" + root of agere, "to drive".

The sense of "to expose (someone or something) to aromatic fumes" is originally a reference to a medicinal or therapeutic treatment.