(Geom.) 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.
... star in the Sword is theta, and is surrounded by the celebrated Nebula of Orion. The telescope shows theta separated into four stars arranged at the corners of an irregular square, and shining in a black gap in the nebula. These four stars are collectively named the Trapezium. The brightest is of the sixth magnitude, the others are of the seventh, seven and a half, and eighth magnitudes respectively. The radiant mist about them has a faint greenish tinge, while the four stars, together with three others at no great distance, ... — Pleasures of the telescope • Garrett Serviss
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