Lewis Short
monstrātĭo (noun F) : id.
* A showing, direction (only in Terence and Vitruv.): defessus sum ambulando: ut, Syre, te cum tuā Monstratione magnus perdat Juppiter,direction,Ter. Ad. 4, 6, 1: solers et expedita monstratio,indication, hint,Vitr. 6, 1, 12.
Charlton T. Lewis, Charles Short, A Latin Dictionary