Rhaetian n.

c. 1600, from Latin Rhætia, ancient name of a district in the Alps and of a Roman province between the Rhine, Danube, and Po; from Rhaeti, Raiti, name of a native people. Hence Rhaeto-Romanic (1867), Rhaeto-Romance in reference to the language or dialects of parts of the Tyrol and southeastern Switzerland. Related: Rhaetic.