trapeze
n.
swing with a cross-bar, used for feats of strength and agility, 1861, from French trapèze, from Late Latin trapezium (see trapezium), probably because the crossbar, the ropes and the ceiling formed a trapezium.
The French, to whose powers of invention (so long as you do not insist upon utility) there is no limit, have invented for the world the Trapeze .... ["Chambers's Journal," July 6, 1861]