▪ I. isogonic, a.1 (n.) Phys. Geog.
(aɪsəʊˈgɒnɪk)
[f. as prec. + -ic.]
Indicating equal angles (of magnetic variation); applied to lines on a map, etc. connecting points of the earth's surface where the magnetic declination, or variation from the true north, is the same; or to a map, etc. exhibiting such lines. Also as n. An isogonic line.
| 1851–9 Sabine in Man. Sci. Enq. 97 The Isogonic lines..have a direct practical importance and value in navigation. 1870 R. M. Ferguson Electr. 27 The lines of equal declination are called isogonic lines; those of equal dip, isoclinic; and those of equal intensity, isodynamic lines. 1876 Davis Polaris Exp. App. 642 With regard to the variations of the compass, as derived from an isogonic chart. 1892 J. Thornton Adv. Physiogr. xvi. §257 These two sets of magnetic lines, isogonics and isoclinics. |
▪ II. isoˈgonic, a.2 Biol.
[ad. Fr. isogonique (A. Pézard 1918, in Bull. Biol. de la France et de la Belgique LII. 24).]
Characterized by isogonism. Of an organ, growing at the same rate as its parent body. So iˈsogony, growth of this kind.
| 1901 In mod. Dicts. 1924 J. S. Huxley in Nature 20 Dec. 895/1 Pézard..has styled the growth of such an organ heterogonic..as opposed to isogonic. 1932 ― Probl. Relative Growth i. ii. 8 An organ which..is growing at the same rate as the body..must be styled isogonic. Ibid. iii. 38 It is justifiable to regard isogony as a special case of heterogony, with growth-coefficiency unity. 1945 Richards & Kavanagh in Clark & Medawar Ess. Growth & Form 219 Isogonic growth is a special case of isotropic growth in which the specific growth-rate in length is the same at every point throughout the organism. |