cist

noun2

1. •
   A crypt cut into rock, chalk, or a tree trunk, especially a coffin formed by placing stone slabs on edge and topping them with a horizontal slab or slabs.

   • A central stone slab cist containing the burial was surrounded by a circles of stones placed on edge, probably to represent the round house in which the deceased had lived. — 2019
2. •
   (historical) A small receptacle for sacred utensils carried in festivals in Ancient Greece.