E. Costantini proposes that this surname would derive from Culin, one of the multiple variants of the name Nicolò, formed through the diminutive Niculin and the subsequent dropping of the first syllable. Costantini documents it in 16th-century Friuli —with the record "Berthul colin" in Gemona, dated 1571— and notes its presence in localities such as Gorizia, Osoppo, Tarvisio, Udine and Ciconicco di Fagagna.

F. De Laurentiis proposes a different line of origin: at the base of the surname could be both generic terms linked to the landscape —the noun "hill" and the derived adjective, which indicated belonging to or provenance from areas of hills— and specific place names of the type Colli or Collina, widely distributed throughout Italy. According to this interpretation, the surname would be of a toponymic or geographical nature, without relation to a given name.

Both proposals are compatible with an independent origin in different regions: Costantini's hypothesis is more pertinent for the Friulian area, while De Laurentiis's points to an origin of peninsular reach.