'Incan' originates from Spanish, specifically the word 'Inca', which comes from Quechua 'Inka', where 'Inka' meant 'ruler' or the name of the ruling class.

'Incan' changed from the English noun 'Inca' with the adjectival suffix '-an' (from Latin '-anus' via Old French/Old English) and eventually became the modern English adjective and noun 'Incan'.

Initially, it meant 'of or belonging to the Inca (people/ruler)', but over time it broadened to refer generally to the Inca civilization, its culture, art, architecture, and people.