Math. [ad. mod.L. lēmniscāta, fem. of L. lēmniscātus adj., adorned with ribbons, f. lēmniscus: see LEMNISC.] a. Geom. The designation of certain closed curves, having a general resemblance to the figure 8. b. Alg. Used attrib. in lemniscate function, one of a class of elliptic functions first investigated by Gauss (Werke III. 404), in connection with formulæ relating to the properties of this class of curves.

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1781.  Chambers’ Cycl. (ed. Rees), Lemnisicate [sic].

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1801.  Encycl. Brit. (ed. 3), Suppl. II. 74/2. Lemniscate.

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1837.  Whewell, Hist. Induct. Sci., XV. v. 218. The rings and lemniscates produced by dipolarizing crystals.

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1873.  G. Salmon, Higher Plane Curves, ii. (1870), 44. The curve being then known as the lemniscate of Bernouilli.

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1879.  Cayley, in Coll. Papers (1896), XI. 65. The formulæ given by Gauss … for the lemniscate functions sin lemn (a±b) and cos lemn (a±b). Ibid. (1891), ibid. (1897), XIII. 196. The elliptic function snl of the lemniscate form.

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