Coenaculum

Coenaculum, the term applied to the eating-room of a Roman house in which the supper (coena) or latest meal was taken. It was sometimes placed in an upper storey and reached by an external staircase.

The Last Supper in the New Testament was taken in the coenaculum, the large upper room cited in St. Mark (xiv.15) and St. Luke (xxii.12).

See also Cenacle

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "". Encyclopædia Britannica. 6 (11th ed.). Cambridge University Press. p. 644. 

...
Wikipedia