A columbarium, also called a cinerarium, is a structure for the reverential and usually public storage of funerary urns holding cremated remains of the dead. The term comes from the Latin columba (dove) and originally solely referred to compartmentalized housing for doves and pigeons, also called dovecotes.
The San Francisco Columbarium
Columbarium wall, with flowers, plaques, and empty niches
Detail of the columbarium at Père Lachaise Cemetery, Paris
A modern columbarium in a small town (Ebingen, Germany)
An urn is a vase, often with a cover, with a typically narrowed neck above a rounded body and a footed pedestal. Describing a vessel as an "urn", as opposed to a vase or other terms, generally reflects its use rather than any particular shape or origin. The term is especially often used for funerary urns, vessels used in burials, either to hold the cremated ashes or as grave goods, but is used in many other contexts.
Ancient Roman urn made of alabaster
Ancient Greek cremation urn ca. 850 B.C.
The Derveni Krater, one of very few large Ancient Greek bronze vessels to survive
The Ashes urn.