| 释义 |
diagonal, a. and n.|daɪˈægənəl|
[ad. L. diagōnālis (Vitruvius), f. Gr. διαγών-ιος from angle to angle, f. διά across + γωνία angle: see -al1 I. 2. Cf. F. diagonal (13th c. in Littré).]
A. adj.
1. Geom. Extending, as a line, from any angular point of a quadrilateral or multilateral figure to an opposite or non-adjacent angular point. (Also applied to a plane extending from one edge of a solid figure to the opposite edge.) Hence gen. Extending from one corner of anything to the opposite corner.
1541[implied in diagonally]. 1563Shute Archit. C iv a, The diagonall line marked B. 1570Billingsley Euclid xi. xxxix. 354 Diagonall lines drawen from the opposite angles. 1660H. Bloome Archit. A b, The square..crossed with two Diagonall lines. 1823H. J. Brooke Introd. Crystallogr. 12 The diagonal plane of a solid..is an imaginary plane passing through the diagonal lines of two exterior parallel planes. 1859R. F. Burton Centr. Afr. in Jrnl. Geog. Soc. XXIX. 156 From east to west the diagonal breadth of Mgunda Mk'hali is 140 miles.
2. More loosely: Having an oblique direction like the diagonal of a square or other parallelogram; lying or passing athwart; inclined at an angle other than a right angle (usually about 45°).
1665[see 4]. 1796Instr. & Reg. Cavalry (1813) 57 By the diagonal march of divisions either to front or rear. 1821Craig Lect. Drawing vi. 350 A supposed diagonal line from the outer corner of each eye. 1831Lardner Pneumat. iv. 257 Every change in the position of the surface of the mercury..will be three times as great in the diagonal barometer as it would be in the vertical one. 1851H. T. De la Beche Geol. Obs. 612 Diagonal arrangements of the minor parts..are very common in many sandstones. 1867Smyth Sailor's Word-bk., Diagonal braces, knees, planks, etc. are such as cross a vessel's timbers obliquely. 1876Mathews Coinage i. 7 On some English coins of last century the milling is diagonal to the edge.
3. Marked with diagonal or oblique lines, or having some part placed diagonally or obliquely.
diagonal bellows: a bellows (in an organ) having its sides inclined at an angle. diagonal cloth: a twilled fabric having the ridges diagonal, i.e. running obliquely to the lists. diagonal couching (in needlework): couching in which the stitches form a zig-zag pattern. diagonal scale: a scale marked with equidistant parallel lines crossed at right angles by others at smaller intervals (e.g. 1/10 of the larger), and having one of the larger divisions additionally crossed by parallels obliquely placed; used for measurement of small fractions (e.g. hundredths) of the unit of length.
a1679Sir J. Moore Math. (1681) 224 Then taking 1 or 10 from any line of equal parts or Diagonal Scale, prick it on AD six times. 1824Gill's Techn. Repos. VI. 199 The proposed Diagonal Pavement in the streets of London. 1876J. Hiles Catech. Organ. viii. (1878) 52 Afterwards diagonal or wedge-shaped bellows came into use. 1879Moseley Naturalist on Challenger 473 A wide patch of diagonal ornamentation upon the abdomen. 1882Caulfeild & Saward Dict. Needlework 152 Diagonal couching..is chiefly employed in Church Work. 1883A. E. Seaton Mar. Engineering 55 Any engine whose cylinders are not perfectly horizontal may..be called Diagonal.
4. Comb., as diagonal-built a., (a boat or ship) having the outer skin consisting of two layers of planking making angles of about 45° with the keel in opposite directions; diagonal-planed a. (see quot. 1805–17); diagonal-wise adv. = diagonally.
1665Phil. Trans. I. 84 They may make up a Cylinder cut Diagonal wise. 1805–17R. Jameson Char. Min. (ed. 3) 212 A crystal is said to be diagonal planed, when it has facets..situated obliquely. 1869R. W. Meade Naval Archit. 416 In diagonal-built boats the skin consists of two layers of planking.
B. n.
1. Geom. A diagonal line; a straight line joining any two opposite or non-adjacent angles of a rectilineal figure (or of a solid contained by planes).
[1563Shute Archit. C ij b, A lyne ouerthwart from the one corner to the other, which line is called Dyagonalis.] 1571Digges Pantom. iv. v. V iv, Wherby the diagonal exceedeth the side pentagonal. 1662Hobbes Seven Prob. Wks. 1845 VII. 62 You pitched upon half the diagonal for your foundation. 1827Hutton Course Math. I. 322 The rectangle of the two diagonals of any quadrangle inscribed in a circle. 1831Carlyle Sart. Res. i. vii. 33 A square Blanket, twelve feet in diagonal. 1847Tennyson Princ. Concl. 27 Betwixt them both, to please them both, And yet to give the story as it rose, I moved as in a strange diagonal, And maybe neither pleased myself nor them. 1871Tyndall Fragm. Sc. (1879) I. iv. 115 The short diagonal of the large Nicol [prism] was in the first instance vertical.
b. A diagonal ‘line’ or row of things arranged in a square or other parallelogram (e.g. of squares on a chess-board).
c. A part of any structure, as a beam, plank, etc., placed diagonally.
1837Goring & Pritchard Microgr. 112 The light stopped by the diagonals of the engiscope. 1853Sir H. Douglas Milit. Bridges 330 The diagonals b c, b′ c′, having the quality of ties. 1874Knight Dict. Mech. I. 691 Diagonal, a timber brace, knee, plank, truss, etc., crossing a vessel's timbers obliquely.
2. = diagonal cloth (see A. 3):
a. a soft material used for embroidery;
b. a black coating for men's wear.
1861Ure Cotton Manuf. (ed. 2) II. 259 A fustian, with a small cord running in an oblique direction..is called diagonal. 1878A. Barlow Hist. Weaving Gloss, Diagonals, fancy lozenge pattern cloths. 1883Daily News 19 Sept. 6/6 Thin meltons, diagonals, and serges. 1890R. Beaumont Colour in Woven Design 268 Diagonals are but plainly coloured. |