From Robert Barret's glossary:
Cuisset, is the armings of a horseman, for his thigh vnto the knees.
Taisses, a French vvord, and is the arming of the thighes, annexed vnto the forepart of the Corslet.
https://quod.lib.umich.edu/e/eebo/A04863.0001.001/1:17?rgn=div1;view=fulltext
Usually authors seem to use the terms interchangeably, but if you want to get specific it seems that the tasses refers to the upper part that goes down to the thigh, and the cuisset refers to the part covering the lower thigh and the knee.
Quote: |
True it is, it is necessarie, for the shocke of a horse to weare a little Cuisset to co∣uer the knee, so ought al the Launtiers to be. We know it by experience; let a horseman be armed, the forepart of his curaces of a light pistoll proofe, his head peece the like, two lames of his pouldrons the like, two or three lames of his tasses of the like proofe, the rest I meane his tasses, cuisses, pouldrons, vambraces, and gauntlets, bee also so light as you can deuise. |
-Sir Roger Williams, A Briefe Discourse of VVarre