Aryan(Britannica):

from Sanskrit arya, “noble”), a people who, in prehistoric times, settled in Iran and northern India. From their language, also called Aryan, the Indo-European languages of South Asia are descended. In the 19th century the term was used as a synonym for “Indo-European” and also, more restrictively, to refer to the Indo-Iranian languages (q.v.). It is now used in linguistics only in the sense of the term Indo-Aryan languages (q.v.).

During the 19th century there arose a notion—propagated most assiduously by the Comte de Gobineau and later by his disciple Houston Stewart Chamberlain (qq.v.)—of an “Aryan race,” those who spoke Indo-European languages, who were considered to be responsible for all the progress that mankind had made and who were also morally superior to “Semites,” “yellows,” and “blacks.” The Nordic, or Germanic, peoples came to be regarded as the purest “Aryans.” This notion, which had been repudiated by anthropologists by the second quarter of the 20th century, was seized upon by Adolf Hitler and the Nazis and made the basis of the German government policy of exterminating Jews, Gypsies, and other “non-Aryans.”