eccentric, a. and n.
(ɛkˈsɛntrɪk)
Forms: 6 eccentrike, 6–9 excentric(k(e, 7–8 eccentrick, 7 ec-, excentrique, 7– eccentric.
[ad. late L. eccentricus, f. Gr. ἔκκεντρος eccentric as opposed to concentric (f. ἐκ out of + κέντρον centre); see -ic; the word is found in all the Romanic langs.: Fr. excentrique (14th c. in Littré), Pr. excentric, It. eccentrico, Sp. excéntrico.]
A. adj.
1. Of a circle: Not concentric with another circle (const. to). Of two or more circles: Not mutually concentric. Chiefly used of circles of which one is within the other. † eccentric orb: in the Ptolemaic astronomy, an orbit not having the earth precisely in its centre (afterwards sometimes used in a Copernican sense: an orbit not having the sun precisely in its centre).
| 1551 Recorde Cast. Knowl. (1556) 247 These two circles..are eccentrike, for that they haue not one common centre. 1621 Burton Anat. Mel. ii. ii. iii. (1651) 159/2 Which howsoever Ptolemy, &c., maintaine to be reall Orbs, excentrick, concentricke. 1656 tr. Hobbes' Elem. Philos. (1839) 431 This annual orb [of the earth] is eccentric to the sun. |
† b. fig. Not agreeing, having little in common. Const. from, to. Obs.
| 1607–12 Bacon Wisdom, Ess. (Arb.) 184 His owne endes, which must needes be often eccentrique to the endes of his Master or State. 1666 Collins in Rigaud Corr. Sci. Men (1841) II. 463 My book of Accounts..is so eccentric to your studies as I thought it unworthy your acceptance. 1670 Sanderson in Ussher Power Princes (1683) Pref., A task..altogether excentrick from their function and calling. |
2. That has its axis, its point of support, etc., otherwise than centrally placed. Cf. B. 2.
| 1647 Ward Simp. Cobler 45 Else the world will be Eccentrick, and then it will whirle. 1743 Savery in Phil. Trans. XLVIII. 177 Large object-glasses for telescopes are not commonly well center'd..I..return'd [two faulty ones] and had two sent me again, as eccentric well nigh as the former ones. 1825 Wood Railroads 148 This eccentric circle is loose upon the axle..a circular hoop.. fits the circumference of the eccentric motion. 1831 J. Holland Manuf. Metals I. 92 That ingenious but simple contrivance the eccentric wheel. |
3. Not centrally placed. Of an axis, etc.: Not passing through the centre.
| 1849 Sir J. Herschel Outlines Astron. iii. §141 (1858) 83 If the axis be excentric. 1882 Vines Sachs' Bot. 203 The organic centre of the transverse section does not usually coincide with the geometrical centre, as is easily seen in the transverse sections of most petioles and horizontal branches with an ‘eccentric’ pith. 1884 Bower & Scott De Bary's Phaner. & Ferns 365 The position of the bundle in the root is from the first slightly eccentric. |
† b. Of a locality: Remote from the centre; out of the way. [So Fr. quartier excentrique.] Obs.
| 1800 T. Jefferson Writ. (1859) IV. 312 [The College] is..eccentric in its position, exposed to all bilious diseases abandoned by the public care. |
c. Phys. (See quot.)
| 1876 Bernstein Five Senses 20 The sensation of sight can only take place..in the brain..and yet we transfer the object seen to the external world surrounding us. This fact is called the law of eccentric sensation. |
† 4. Misused for: Having no centre. Obs.
| 1633 T. Adams Exp. 2 Peter iii. 7 Only that is eccentric, which was never made. 1652 Benlowes Theoph. ii. xli. 28 Deaths hell deaths Self out-deaths, Vindictive Place!.. Excentrick Space! 1681 tr. Willis' Rem. Med. Wks. Voc., Eccentric, without centre. |
5. Of orbital motion: Not referable to a fixed centre of revolution; not circular. Of a curve, an elliptic, parabolic, or hyperbolic orbit: Deviating (in greater or less degree) from a circular form.
| 1642 Howell For. Trav. 77 Let these Lights..be kept from irregular and eccentrique motions. 1692 Bentley Boyle Lect. vii. 247 They could not acquire such Revolutions in Ellipses very little Eccentric. 1796 Morse Amer. Geog. I. 32 Like other planets moving about the sun in very eccentric ellipses. 1866 Sir J. Herschel Fam. Lect. Sc., Comets 104 A comet moves round the sun..in an immensely elongated, or as it is termed a very eccentric, ellipse. |
b. transf. Of a heavenly body: Moving in an orbit deviating (more or less) from a circle.
| a 1721 J. Keill Maupertuis Diss. (1734) 63 The Comets are no more..than very excentric Planets. a 1791 Wesley Serm. lxix. 8 Wks. 1811 IX. 249 Those horrid, eccentric orbs. 1816 J. Smith Panorama Sc. & Art I. 581 When very eccentric planets or comets go round any flat star, in orbits much inclined to its equator. |
c. eccentric anomaly: the true anomaly of a planet moving in an eccentric orbit (opposed to the mean anomaly). eccentric equation: see equation.
6. fig. Regulated by no central control. a. Of actions, movements, and things in general: Irregular, anomalous, proceeding by no known method, capricious.
| c 1630 Drummond of Hawthornden Poems 195 Finding all eccentrick in our times. 1792 Burke Pres. St. Aff. Wks. I. 586 The eccentrick aberration of Charles the Second. 1848 Macaulay Hist. Eng. I. 657 This eccentric clemency has perplexed some writers. |
b. Of persons and personal attributes: Deviating from usual methods, odd, whimsical.
| 1685 86 Loyal Poems, Shaftesbury's Farew. 6 The brightest, yet the most excentrick Soul. 1695 Ld. Preston Boeth. ii. 68 The Extravagance of Excentrick and irregular Desires. 1771 Mackenzie Man Feel. xxxiv. (1803) 61 His motives were rather excentric. 1802 M. Edgeworth Moral T. (1816) I. Pref. 7 [Forester is the picture of] an eccentric character. 1836 H. Rogers J. Howe ii. (1863) 19 That great, though unequal and eccentric genius. |
7. a. quasi-adv. b. absol. quasi-n.
| 1672 Dryden Conq. Granada i. v. i, He moves excentrique, like a wand'ring Star. 1870 Lowell Among my Bks. Ser. i. (1873) 203 Wordsworth never quite saw the distinction between the eccentric and the original. |
B. n.
† 1. [= eccentric circle, orb; see A. 1.] In Ptolemaic astronomy: A circle or orbit not having the earth precisely in its centre. Obs. exc. Hist.
| [1398 Trevisa Barth. De P.R. viii. xi. (1495) 317 The fyrste meuynge of a planete..is a cercle that hyghte Ecentricus.] 1561 Eden Art Navig. i. xx. 22 Eccentricke, is a circle which hath his center distant..from the center of the worlde. 1646 Sir T. Browne Pseud. Ep. 293 The Perigeum or lowest part of the eccentric. 1724 Watts Logic (1736) 225 Excentricks and Epicycles of Ptolomy. 1783 W. F. Martyn Geog. Mag. I. Introd. 14 A number of circles called eccentrics and epicycles. |
| fig. a 1660 Hammond Wks. IV. 551 Reserving..somewhat for common calamities, somewhat as it were for the universal motion of the whole body, somewhat for eccentricks. |
2. Mech. A circular disc fixed on a revolving shaft, some distance out of centre, working freely in a ring (the eccentric strap), which is attached to a rod called an eccentric rod, by means of which the rotating motion of the shaft is converted into a backward-and-forward motion. Its most frequent use is for working the slide-valve of a steam-engine. (Earlier eccentric circle, motion; see A. 2).
| 1827 Specif. Mandelay's Patent No. 5531 It consists..in the application of an eccentric to work the slide [valve]. 1838 Public Wks. Gt. Brit. 69 The slides are worked by four fast eccentrics..instead of two loose ones. 1881 Mechanic §657. 302 The set screw in the eccentric shall be downwards. |
3. [Cf. A. 6 b.] A person whose conduct is irregular, odd, or whimsical.
| 1832 Scott St. Ronan's Introd., Men of every country playing the eccentric. 1850 Kingsley Alt. Locke vi. (1879) 65, I have given no description of the old eccentric's abode. |
C. attrib. and Comb. a. In various parts connected with the eccentric that works the slide-valve in a steam-engine, as eccentric-catch, eccentric-hook, eccentric-rod. Also eccentric-hoop, -ring, or -strap, the ring in which the eccentric revolves.
b. In various machines or parts of machines, whose distinctive feature is that they are worked by an eccentric wheel or depend upon an eccentric arrangement; as eccentric-arbor, eccentric-chuck, eccentric-cutter (in Turning), eccentric-engraving, eccentric-fan, eccentric-gear, eccentric-pump.
| 1859 Handbk. Turning 57 Eccentric turning..includes all the various..work for which the powers of a lathe are..celebrated. Ibid. 87 Eccentric chuck. 1884 F. J. Britten Watch & Clockm. 100 When the three screws are loosened the two parts of the eccentric arbor may be shifted. |