The surname Bassan and its variants originate mainly from place names of northern Italy, especially in the Veneto and Lombardy area. According to E. Rossoni, it derives directly —or through affectionate forms— from the place name Bassano del Grappa (Vicenza), which indicates a geographical origin linked to people coming from that locality. He also documents its historical presence in areas such as San Bonifacio (Verona) in the 16th century and Battaglia Terme (Padua) in the 17th century.

Along the same lines, F. De Laurentiis confirms its toponymic origin, noting that it can derive from various places called Bassano in northern and central Italy, such as Bassano del Grappa (VI), Bassano Bresciano (BS), Bassano (VA) or San Basiano (CR). He also stresses that, in relation to Bassano del Grappa, the surname was frequent among Jewish communities established there, which adds a historical-cultural nuance to its diffusion.

On the other hand, F. De Laurentiis raises a possible alternative derivation from the personal name Bassano, spread especially in Lombardy through the cult of Saint Basianus, a contemporary of Saint Ambrose and patron of Lodi. Taken together, the various interpretations agree in pointing to a mainly toponymic origin, although in some cases an anthroponymic base linked to local religious tradition is not excluded.