The Collaborative International Dictionary of English v.0.48:
Tuille \Tuille\ (tw[i^]l), n. [Cf. F. tuile a tile.] In plate armor, a suspended plate in from of the thigh. See Illust. of Tasses. [1913 Webster]WordNet (r) 3.0 (2006):
tuille n 1: armor plate that protects the hip and thigh