tra·pe·zi·um / trəˈpēzēəm/ • n. (pl. -zi·a / -zēə/ or -zi·ums ) 1. Geom. a type of quadrilateral: ∎  a quadrilateral with no sides parallel. Compare with trapezoid. ∎ Brit. a quadrilateral with one pair of sides parallel. 2. (also os trapezium) Anat. a bone in the wrist below the base of the thumb.

trapezium

trapezium (geom.) irregular quadrilateral XVI; quadrilateral having only one pair of opposite sides parallel XVII. — late L. — Gr. trapézion, f. trápeza table, for *tetra-peza, f. TETRA- + IE. *ped- FOOT.
So trapezoid quadrilateral no two sides of which are parallel. XVIII. — modL. trapezoidēs — late Gr. trapezoeidés.

Tra·pe·zi·um / trəˈpēzēəm/ (the Trapezium) Astron. the multiple star Theta Orionis, which lies within the Great Nebula of Orion and illuminates it. Four stars are visible in a small telescope and two more with a larger telescope.

trapezium (tră-pee-ziŭm) n. a bone of the wrist (see carpus). It articulates with the scaphoid bone behind, with the first metacarpal in front, and with the trapezoid and second metatarsal on either side.