As an adaptation of the Latin Arianus, referring to Iran, 'Aryan' has "long been in English language use". Its history as a loan word began in the late 1700s, when the word was borrowed from Sanskrit ā́rya- meaning dignified person or of noble birth. When it was determined that Iranian languages — both living and ancient — used a similar term in much the same way (but in the Iranian context as a self-identifier of Iranian peoples), it became apparent that the shared meaning had to derive from the ancestor language of the shared past, and so, by the early 1800s, the word 'Aryan' came to refer to the group of languages deriving from that ancestor language, and by extension, the speakers of those languages. Then, in the 1830s, based on the erroneous theory that words like "Aryan" could also be found in European languages, the term "Aryan" came to be used as the term for the Indo-European language group, and by extension, the speakers of those languages. In the 19th century, "language" was still considered a property of "ethnicity", and thus the speakers of the Indo-European languages came to be the so-called "Aryan race", as contradistinguished from the so-called "Semitic race". By the late 19th century, the notions of an "Aryan race" became closely linked to Nordicism, which posited Northern European racial superiority over all other peoples (including Indians and Iranians). This "master race" ideal engendered both the "Aryanization" programs of Nazi Germany, in which the classification of people as "Aryan" and "non-Aryan" was most emphatically directed towards the exclusion of Jews.

By the end of World War II, the word 'Aryan' had become firmly associated with the racial delusions and atrocities commited by the Nazi regime. In colloquial modern English it is typically used to signify the Nordic racial ideal promoted by the Nazis. In present-day India, the original ethno-linguistic signifier has been mostly lost, the denotation having been semantically replaced by other, secondary, meanings. In Iran, the original self-identifier lives on in ethnic names like "Alani", "Ir", and in the name of Iran itself. In present-day academia, the terms "Indo-Iranian" and "Indo-European" have made most uses of the term 'Aryan' obsolete, and 'Aryan' is now mostly limited to its appearance in the term "Indo-Aryan" to represent (speakers of) North Indian languages. Notions of an "Aryan race" only survive in the context of fascist nationalism, in which nationhood is defined by ancestry. Recent genetic analysis of the Indian population do support the hypothesis of two genetic strains there, one related to modern Europeans and the other unique to southern India.