Definition of "zoarium"

The zoarium is unilaminate or bilaminate.

1896, John W. Gregory, Catalogue of the Fossil Bryozoa in the Department of Geology, British Museum, page 117

Cellariiform, the orifices nearly confined to the convex frontal and lateral surfaces; the basal surface with a strong median calcareous keel, almost concealed by a flat membranous epitheca, which covers the whole zoarium […]

1957, Sidney Frederic Harmer, The Polyzoa of the Siboga Expedition, page 1106