a. (and sb.). Also 4 -sentrik, -sentryk, 7 -centrique. [ad. F. concentrique, or med.L. concentric-us (14th c. in Du Cange), f. con- together + centr-um circle: cf. centric, eccentric, the ultimate type being Gr. κεντρικός, of the center, central.]
A. adj.
1. Having a common center, described about the same center. (Said of circles and spheres, etc.)
c. 1391. Chaucer, Astrol., I. § 16. Degres of this Bordure ben answering & consentrik to the degrees of the Equynoxial. Ibid., I. 17. The heued of capricorne turnyth euermo consentryk vp-on the same cercle.
1621. Burton, Anat. Mel., II. ii. III. (1676), 159/2. Which howsoever Ptolomy, Alhasen, Vitellio, Purbachius, Maginus, Clavius, and many of their associates stiffly maintain to be real Orbes, eccentrick, concentrick, circles æquant, &c. are absurd and ridiculous.
1692. Bentley, Boyle Lect., viii. 266. The concentric Revolutions of the Planets about the Sun.
1706. Sibbald, Hist. Picts, in Misc. Scot., I. 105. An inner wall, concentric with, and distant about two feet from the other.
1726. trans. Gregory’s Astron., I. 3. Not perfect Circles, concentric to the Sun.
1808. Asiat. Res., VIII. 289. The Baudd’hists of Tibet represent these zones as so many concentric squares.
1880. G. Allen, in Mind, V. 451. A gradual regression or concentric widening of æsthetic feeling around this fixed point.
fig. 1603. Daniel, Epist., Wks. (1717), 350. It hath a Course Concentrick, with the Universal Frame Of Men combin’d.
a. 1711. Ken, Hymnarium, Poet. Wks. 1721, II. 75. Till my will mov’d concentrick with thy own.
1871. Tyndall, Fragm. Sc. (ed. 6), II. ii. 29. Not until this … is the law of reason rendered concentric with the law of nature.
2. Specific uses.
a. Bot., as in Concentric bundle: a fibro-vascular bundle in which the bast tissue surrounds the wood tissue, or vice versa. (Opposed to collateral.)
1878. McNab, Bot. (ed. 4), 45. In the ferns and lycopods, and in some monocotyledons, where the phloem completely surrounds the xylem the bundles may be called concentric.
1884. Bower & Scott, De Bary’s Phaner., 467. The number of the concentric cambium-like layers varies.
b. Conch. (See quot.)
1854. Woodward, Mollusca (1856), 102. The operculum is … Concentric, when it increases equally all round.
1866. Tate, Brit. Mollusks, iii. 46. Its mode of growth is concentric.
c. Biol., etc.
Concentric cells: ‘cells which contain another cell.’ Concentric contraction: ‘a muscular contraction which results in the approximation of the two ends, and the consequent shortening, of the muscle.’ Concentric differentiation: ‘that process by which, when any organic or inorganic substance exerts a play of forces with the surrounding medium, the superficial differ from the deeper parts’ (Syd. Soc. Lex.).
d. Geol. and Min. Concentric structure: a structure in which parallel layers, differing in color or composition, lie round a common center.
1811. Pinkerton, Petral., I. 223. If the kernels … retain their uniform concentric tints.
1842. H. Miller, O. R. Sandst., xiii. (ed. 2), 281. Their concentric condition shows the chemical influences of the decaying animal matter.
e. Mil. Concentric fire: firing concentrated on one point.
1850. Alison, Hist. Europe, VIII. li. § 62. 524. The severity of the concentric discharges was so great that this gallant regiment wavered and broke.
1852. Blackw. Mag., LXXII. 355. Subject every day to the concentric fire of the Radical press.
1875. trans. Comte de Paris’ Civil War Amer., II. 348. [The brigade] soon found itself exposed to a concentric fire.
f. Pathol. Concentric hypertrophy: A term applied to hypertrophy of the heart when the cavities are smaller than natural.
1871. Sir T. Watson, Princ. & Pract. Phys., II. 270.
1876. trans. Ziemssen’s Cycl., VI. 211.
† 3. catachr. = CONCENTRATED 2. Obs. rare–1.
1771. Phil. Trans., LXI. 340. Acids never are given in so concentric a state.
B. sb. A concentric circle or other figure.
1551. Recorde, Pathw. Knowl., I. Concentrikes, that is to saie, circles drawen on one centre.
1603. Florio, Montaigne, II. xii. (1632), 301. These Epicycles, Excentriques, and Concentriques, which Astrology useth.
a. 1656. Hales, Gold. Rem. (1638), 358. Such Concentricks or Epicycles of Sympathies and Antipathies.
