xystum Share definition Flag A Xystum is an architectural term. It can refer to a wall, promenade, alley or open path. It can also refer to an atrium, ambulacrum, or parvis in front of a basilica. im seein' ants crawling on the xystum! xystum by xgs November 13, 2010 0 0 Get merch Get the xystum mug. Buy Now — $32.95 See more merch
