elliptic

Etymology

From Ancient Greek ἐλλειπτικός (elleiptikós), from ἐλλείπω (elleípō, “I leave out, omit”). Surface analysis ellipse + -tic.

adj

1. (geometry) Of or pertaining to an ellipse.
   In this chapter, the history of solving elliptic problems by direct marching methods is reviewed. 1995, Patrick J. Roache, Elliptic Marching Methods and Domain Decomposition, page 1
2. (mathematics) Of or pertaining to a broad field of mathematics that originates from the problem of calculating arc lengths of an ellipse.
   elliptic integral
   elliptic function
   elliptic curve
3. (mathematics, in combination, of certain functions, equations and operators) That has coefficients satisfying a condition analogous to the condition for the general equation for a conic section to be of an ellipse.
   elliptic partial differential equation
   elliptic operator
   elliptic regularity
4. (botany, of leaves) Oval, with a short or no point.

noun

1. An elliptical function, equation, path, etc.
   The Planetary Paths I trace, / Exploring Realms of boundleſs Space; / Elliptics, Angles, Cubes, and Curves, / In me ſupply the Place of Nerves; […] 1765, John Nichols, “[New Ænigmas, to be answered next Year.] (2.) Ænigma 192”, in The Gentleman’s Diary, or The Mathematical Repository; an Almanack[…], London: […] [T]he Company of Stationers, page 45
   Two men were smoking over a bottle of wine at one table; they were talking of parabolics and elliptics, and describing diagrams on the table with a wet finger; […] 1807, Manuel Alvarez Espriella [pseudonym; Robert Southey], “Mail Coaches.—Mr. Palmer ill-used.—Vicinity of Birmingham.—Collieries on fire.—Stafford.—Stone.—Newcastle-under-Line.—Punishments for Scolding.—Cheshire.—Bridgewater Arms at Manchester.”, in Letters from England, volume II, London: […] Longman, Hurst, Rees and Orme,[…], page 137
   Diagrams geometric, on parchmental scroll; / Circles, ovals, elliptics and such, / He sure figures will tell what is inside the knoll, / And tho far under ground, he’s in touch / With the hidden deposits of mineral ore, / And lost channels ’neath mountains he feels: […] 1916, “Platinum Bill” [pseudonym; Wilfrid Robert Smith], “The Dreamster”, in Under the Northern Lights, Portland, Ore.: The Columbia Printing Co., stanza II, pages 32–33
   The fix points of hyperbolics and parabolics in F must lie on the fixed circle C, while the fixed points of elliptics in F are inverse with respect to C. 1987 December, Benjamin Fine, “Fuchsian embeddings in the Bianchi groups”, in Canadian Journal of Mathematics, volume XXXIX, number 6, page 1435