'archil' originates from Romance languages influenced by Arabic; it passed into English via Medieval Latin/Old French from Spanish/Portuguese forms (e.g. 'orchilla'), ultimately reflecting Arabic origin 'al-qil' (the article 'al-' + root referring to a lichen used for dye).

'archil' changed from Medieval Latin/Old French/Spanish forms such as 'orceille' / 'orchilla' (and variants like 'orchil') and eventually entered modern English as 'archil' (with 'archils' as the plural).

Initially, the term referred specifically to the lichen material used to make a purple dye; over time it continued to denote both the dye product and the lichen source, a usage that persists in technical and historical contexts.