The term relic, literally “what remains,” from Christian religious culture, and so familiar there, has no literal translation in neither Arabic, Turkish, Persian, nor Urdu. The equivalent term used for relic in Islam is āthār (plural of athar: “effect, trace”), covering a much more general meaning than relic, or, in the Persianate world, including the Indian Subcontinent, yadgār, which refers more to the idea of memory and remembering than to the idea of remains, especially physical remains.
Collinet, Annabelle, Parsapajouh, Sepideh, & Boivin, Michel. (2021). Bodies & Artefacts: Relics and Other Devotional Supports in Shiʿa Societies in the Indic and Iranian Worlds: An Introduction. Journal of Material Cultures in the Muslim World, Volume 1 (Issue 1-2), 191-198. https://doi.org/10.1163/26666286-12340008