diametral, a. and n.
(daɪˈæmɪtrəl)
[a. OF. dyametral (14th c. in Godef. Suppl.; mod.F. diamétral), ad. med.L. diametrālis, f. diametrus diameter: see -al1.]
A. adj.
1. Of or relating to a diameter; of the nature of or constituting a diameter.
diametral plane: (a) Geom. a plane passing through the centre of a sphere or other solid; (b) Cryst. a plane passing through two of the axes of a crystal (see diametric 1).
| 1555 Eden Decades 6 An other Ilande..whose Diametral syde extendynge frome the Easte to the weste, they iudged to bee a hundreth and fyftie myle. 1668 Culpepper & Cole Barthol. Anat. ii. iii. 90 The Diametral wideness of the lower Belly. 1676 Moxon Print Lett. 46 Through this Circle draw a..Diametral line. 1833 Herschel Astron. iii. 151 In the orthographic projection, every point of the hemisphere is referred to its diametral plane or base. 1865 W. S. Aldis Elem. Solid Geom. vi. (1886) 85 The locus of the middle points of a system of parallel chords of a surface is called the diametral surface of the system. 1877 Huxley Anat. Inv. Anim. iii. 162 The diametral folds of the oral aperture. 1881 Maxwell Electr. & Magn. I. 12 A diameter of an ellipsoid and its conjugate diametral plane. |
† b. Forming, or situated in, a straight line. Obs.
| 1594 Blundevil Exerc. iii. i. xv. (ed. 7) 307 When the Sunne, the Earth, and the Moone be met in one selfe diametrall line. 1647 H. More Song of Soul i. i. xlvii, The Sunne and Moon combine, Then they're at ods in site Diametrall. |
† 2. Arith. diametral number: one that is the product of two factors the sum of whose squares is a square. (Cf. diameter 2 d.) Obs.
Thus 32 + 42 = 52; then 3 × 4 = 12 is a diametral number.
| 1557 Recorde Whetst. C iv b. 1674 S. Jeake Arith. (1696) 179 Diametral numbers..are produced as Oblongs, by multiplying their proper parts together. Ibid. 181 All Diametral Numbers do set forth a Plain Rectangled Triangle, having all 3 Sides known. |
† 3. = diametrical 2. Obs.
| 1628 Donne Serm. lxxii. 726 There is not so direct and Diametrall a contrariety between the Nature of any Sinne and God, as betweene him and Pride. 1641 Ld. J. Digby Sp. in Ho. Com. 21 Apr. 11, I see the best Lawyers in diametrall opposition. 1666 Sancroft Lex Ignea 22 Your own Oppositions direct and Diametral to God. 1768 Life Sir Barth. Sapskull I. 56 The genius of pleasure is a diametral contradiction to the spirit of trade and commerce. |
† B. n. Obs.
1. A diametral line, diameter.
| 1658 Sir T. Browne Gard. Cyrus iii. 56 The incession or locall motion of animals is made..by decussative diametrals, Quincunciall Lines and angles. 1676 Moxon Print Lett. 47 Through the Diametral c, d, draw another Diametral line. |
2. A diametral number: see A. 2.
| 1674 S. Jeake Arith. (1696) 184 If 540, or 432, etc. be Diametrals, then 54,000 and 43,200 be the like. |