The term "fumé" or "smoked" has two implications: one linked to the grape, the other to the land...
The Pouilly Fumé grape is derived from the Sauvignon blanc, with egg-shaped berries in tight clusters resembling tit's eggs. When mature these berries are covered in a smoke-coloured, grey bloom, which explains why the Pouilly wine growers talk amongst themselves about Blanc fumé (smoked white) to describe the Sauvignon grape or wines produced from it.
Pruine grise

The word fumé also refers to the incomparable, universally-recognized aromas and bouquet (or fumet - smokey aroma - the famous gun flint aroma, released by rubbing two flints together), which comes from the outstanding land of Pouilly/Loire vineyards. It is this sweet-smelling land that the poet Georges Blanchard has described so perfectly in the local Nevers patois, in a poem entitled "L' vin d' Pouilly" :

Pouilly, si ton nom vagabonde
Jusque dans les pays pardus,
Si t'es connu du bout du Monde,
Té l'doué au jus d'tes pieds tordus.

Té l'doué au soleil, à la terre,
A tout s'qui dounne à ton raisin
Un sacré foutu caractère
Qui I'fait différent d' son vouésin.