E. Costantini explains that this surname derives from the personal name Cjàndi or Candido (formerly written Chiandi), to which the diminutive-affectionate suffix -ùs is added. As old documentation, he mentions a Zuan Chianduzzo di Gemona recorded in Osoppo in 1614. He notes that Chiandussi is concentrated in localities such as Gemona, Pozzuolo, Udine and Tavagnacco, while the variant Chiandusso appears in Majano.

E. Rossoni agrees on the Friulian origin and on the derivation from the familiar forms Cjandi or Chiandi, a regional version of Candido, and proposes that the surname would be equivalent approximately to "the Candidinos". He adds that both Chiandussi and its variant Chiandusso are very rare surnames, peculiar to the Udine area.