Category:Trapezium

Tra*pe"zi*um, n.; pl. E. Trapeziums, l. Trapezia. Etym: [nl., fr. Gr. Tetra-) + foot.]

1. (geom.)

Defn: a plane figure bounded by four right lines, of which no two are parallel.

2. (anat.) (a) a bone of the carpus at the base of the first metacarpal, or thumb. (b) a region on the ventral side of the brain, either just back of the pons varolii, or, as in man, covered by the posterior extension of its transverse fibers.