The authors agree that the surname derives from Fumèo or Fumè, a regional variant of Tomèo, an abbreviated and affective form of Bartolomèo or of Tommasèo (of Tommaso). This variant reflects the adaptation in f of the Greek-Byzantine th Latinized in Bartholomaeus and Thomasus. The name Fomeus is documented from 1240, and in the Milanese dialect the church of San Tommaso was called san Fumè.

E. Rossoni notes that the surname Fumei, absolutely very rare, seems to be of Venetan origin, probably of the Treviso area. Related forms show differentiated geographical distributions: Fumelli appears in Rome, in Marino and in Cagli, in the Urbino area; Fumeo, very scarce, is peculiar to Perledo, in the Lecco area; Fumo seems peculiar to the gulf of Naples and to the Salerno area; Fumi has presence in the Piacenza area, between Siena and Grosseto, and in Lazio. Rossoni also mentions as an early trace of the transformation into a surname the painter G.B. Fumeo, active in Perledo in the second half of the 16th century.