The term “Aryan” has occupied a decisive position in the intellectual history of South Asia and the modern Western world. It has moreover played a deeply menacing part in the political history of Europe. During the heyday of the term, its meaning and reference was the object of a struggle between a linguistic and humanistic understanding of “Aryan” and racial, biological-anthropological usage. This struggle was scholarly and scientific, and at the same time intertwined with the ideological self-understanding of different groups. This article highlights the pivotal moments in the history of the concept and its relationship to similar terms such as “Nordic” and “Caucasian.”