— trapezial , adj.
/treuh pee"zee euhm/ , n. , pl. trapeziums, trapezia /-zee euh/ .
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.
[ 1545-55; trapézion kind of quadrilateral, lit., small table, equiv. to trápez ( a ) table (shortening of * tetrapeza object having four feet, equiv. to tetra- four + péza foot, akin to poús, podós; see TETRA-, FOOT) + -ion dim. suffix ]