xystus (—Hall) the name of the luxuriously-adorned garden back of the peristyle.
There are other similar instances as in the case of "xystus," "prothyrum," "telamones," and some others of the sort.
The xystus was a level piece of ground, in front of a portico, divided into flower-beds of various shapes by borders of box.
In Rome this custom prevailed, at least since the pontificates of xystus and Telesphorus (about 120).
Then they crossed the xystus to the peristyle, and went along a carpeted corridor to the atrium.