B. Zuanella describes this surname as endemic to the small hamlet of Altana, in the Natisone valley, from where it later emigrated towards the bottom of the valley. He notes that it has been transcribed in very diverse forms, under which the original form Čačič can be perceived (or Čjačič, with an added -i- to facilitate the pronunciation), given that the Slovene letter č was formerly transcribed with the digraphs ch and gh, or with the Latin letters c, g and z. Zuanella warns that the current pronunciation Kjačič is incorrect and results from applying modern rules to an old spelling.

On the origin, both authors agree that the surname derives from the onomatopoeic word of child language čàča, which means "papa" or "father", with the suffix -ič. Zuanella adds that this word has disappeared from the Slovene dialect of the Natisone but is preserved in the Slovene dialect of the Torre. E. Rossoni specifies that the form Chiacig results from an Italianization of Čjačič with alteration of the suffix into -ig, and suggests that it could have been used to identify the son of a prominent figure. Both place the surname in the Valli del Natisone, in the Udine area, in the region of Friuli-Venezia Giulia.