The Sanskrit noun hapuṣā-, whose etymology has not been clarified so far, indicates an ingredient of medical preparations of the classical Āyurvedic tradition. Though its meaning is not clearly specified in the standard Sanskrit dictionaries, the word denotes ‘juniper’ (Juniperus communis Linn.) according to specialist literature. This article argues that Sanskrit hapuṣā- is a loanword from an Eastern Middle Iranian *haβursā- connected with Avestan hapərəsī- and numerous New Iranian words. The term denoted a plant growing only in the far North-West of ancient India and more commonly in Iranian-speaking regions. It first entered the Gāndhārī Prakrit used in commercial relations on the Indo-Iranian linguistic border, as shown by the typical adaptation of Eastern Iranian *haβursā- to Gāndhārī *havuṣā-, and finally reached Sanskrit, where it was adapted to Classical Sanskrit phonology. Sanskrit hapūṣā- was eventually borrowed into Khotanese as a technical term.