from
The Collaborative International Dictionary of English v.0.48
Tetragonal \Te*trag"o*nal\, a.
1. (Geom.) Of or pertaining to a tetragon; having four angles
or sides; thus, the square, the parallelogram, the
rhombus, and the trapezium are tetragonal fingers.
[1913 Webster]
2. (Bot.) Having four prominent longitudinal angles.
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3. (Crystallog.) Designating, or belonging to, a certain
system of crystallization; dimetric. See {Tetragonal
system}, under {Crystallization}.
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