surviving memorial of something past.

an object having interest by reason of its age or its association with the past: a museum of historic relics.

a surviving trace of something: a custom that is a relic of paganism.

something kept in remembrance; souvenir; memento.

Ecclesiastical. (especially in the Roman Catholic and Greek churches) the body, a part of the body, or some personal memorial of a saint, martyr, or other sacred person, preserved as worthy of veneration.