[n. of action f. TRISECT v., after L. sectiōnem SECTION: see -TION, and cf. F. trisection (1690 in Hatz.-Darm.).] The action of trisecting; division into three equal parts; rarely gen. division into three.

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1664.  Power, Exp. Philos., III. 187. The Trisection of an Angle.

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1786.  Phil. Trans., LXXVI. 16. The division of the arc of 90 … required trisections and quinquesections.

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1842.  De Quincey, Pagan Oracles, Wks. 1858, VIII. 193. Into this trisection I shall decompose the coarse unity of the question presented by Van Dale.

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1885.  Leudesdorf, Cremona’s Proj. Geom., 295. The point Q is one of the points of trisection of the arc.

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