reliquary

Borrowed from Middle French reliquaire, from Late Latin reliquiarium, from Latin rēliquia ("a relic"), the noun use of reliquus ("left behind"), itself from relinquō ("to relinquish"), formed from re- ("again") and linquō ("to leave"), tracing back to the Proto-Indo-European root *leykʷ-.

The word grew directly from the Latin idea of something 'left behind' — a relic — into the specific noun for the vessel made to hold such remains.

It shares its Latin root with relinquish, since both descend from relinquō, 'to leave behind.'