Pronunciation: (tru-pē'zē-um),[key] —n., —pl.-zi•ums, -zi•aPronunciation: (-zē-u).[key] 1. Geom. a. (in Euclidean geometry) any rectilinear quadrilateral plane figure not a parallelogram.
b. a quadrilateral plane figure of which no two sides are parallel.
c. Brit.trapezoid (def. 1a).
2. Anat.a bone in the wrist that articulates with the metacarpal bone of the thumb.