What do you call a building containing crypts or vaults of entombment?

A building that contains crypts or vaults of entombment is specifically referred to as a mausoleum. This term denotes a structure designed as a burial place that is often grand and architecturally significant, serving both a functional purpose for entombment and a memorial purpose to honor the deceased. Mausoleums can vary in size and design, taking many forms from simple to highly elaborate, and they are designed to house the remains of one or more individuals, making them distinct from other burial places such as simple tombs or structures purely for cremated remains.

In contrast, a tomb typically refers to a grave or a burial chamber and may not encompass the grandeur or design characteristic of a mausoleum. A columbarium specifically describes a structure for housing urns containing cremated remains, so it does not apply to the idea of large vaults for traditional burials. A chapel is a place of worship and is unrelated to the concept of entombment, focusing instead on spiritual gatherings. Thus, the term mausoleum is the most accurate choice for describing a building designed for crypts and vaults of entombment.