From Persian روشنی (rawshanī), meaning "brightness" or "light," derived from روشن (rawshan, "bright, illuminated"). Persian was the prestige literary language of the Indian subcontinent for centuries, and thousands of everyday Hindi words — especially in the emotional and sensory register — have Persian roots. रोशनी entered Hindi via Hindustani and has fully displaced older Sanskrit alternatives like प्रकाश in many colloquial contexts.

रोशनी is deeply embedded in Indian cultural life. Diwali, the most widely celebrated Hindu festival, is literally the "festival of lights" (दीपावली), and रोशनी is the word most commonly used in songs, poetry, and everyday speech to describe its glow. Metaphorically, a teacher, a child, or a moment of understanding can all be called किसी की ज़िंदगी की रोशनी ("the light of someone's life"). Note: do not confuse with प्रकाश (prakāsh), which is the more formal/Sanskrit term for light and is also used as a common given name.