The authors agree that the surname derives from the Latin term sella, which designates a mountain pass, a col or a natural depression between two elevations. This element was widely used in the toponymy of alpine and pre-alpine zones, and gave rise to numerous place names from which the surname arose to identify those who lived near one of these geographic features or came from a place so named.

F. De Laurentiis adds a different perspective: the surname may also have its base in nicknames and trade names derived from sella, in reference to one who makes or uses saddles. He notes that the place name Sella is widely diffused throughout Italy as an indicator of a pass across a mountain ridge, which would explain the independent formation of the surname in different regions.

E. Rossoni specifies the geographic distribution: the surname is present throughout northern Italy, with a nucleus in the Vicenza area —which could derive from the place name Vallesella or from Monte Sella—, another in the north of the Milan area, and another in the Novara and Biella areas. Rossoni also notes that it may derive from the late Latin name Sella, documented in Genesis.

The surname presents multiple independent lines of origin (ceppi), arisen in different regions without a direct relation between them. Besides the nuclei noted by Rossoni, historical presences are documented in Trentino-Alto Adige and in the Carnia, an alpine zone of northern Friuli-Venezia Giulia, territories where the term has a clear and rooted toponymic use.