Pl. -a or -ons. [a. Gr. τετράπλευρον a figure with four sides, f. τετρα-, TETRA- + πλευρόν rib, side.]

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  1.  A square column.

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1837.  Penny Cycl., IX. 315/1. Square pillars or tetrapleurons, with either a statue, or a caryatid figure standing before.

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  2.  Morphol. Pl. Tetrapleura: Organic forms with bilateral symmetry having four antimeres or corresponding opposite parts. Cf. DIPLEURA.

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1883.  [see DIPLEURA].

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  Hence Tetrapleural a., Morphol., zygopleural with four antimeres.

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1891.  in Cent. Dict.

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