| 释义 |
▪ I. axis1|ˈæksɪs|
Pl. axes |ˈæksiːz|.
[a. L. axis axle, axle-tree, pivot, axis of the earth, heavens, etc., cogn. with OE. eax: see ax n. Used for various figurative and transferred senses of axle.]
I. Axis of rotation or revolution.
1. a. The axle of a wheel. ? Obs.
wheel and axis, axis in peritrochio: the Wheel-and-Axle, one of the mechanical powers.
a1619M. Fotherby Atheom. ii. xi. §1 The weightines of the wheele doth settle it vpon his Axis. 1725Bradley Fam. Dict. s.v. Windmill, Like unto the Axis of a Cutlers Grind-Stone. 1796Hutton Math. Dict. I. 178 To construct an axis in peritrochio. 1822J. Imison Sc. & Art I. 37 The wheel and axis may be considered as a kind of perpetual lever.
b. fig. The ‘pivot’ on which any matter turns.
1860Motley Netherl. (1868) I. v. 169 The axis of the revolt was the religious question.
2. Phys.
a. A tooth or process on the second cervical vertebra, upon which the head is turned.
b. The vertebra which has the process.
1694Salmon tr. Diemerbroeck's Anat. iv. xii. (1714) 249 Axis..is a name which rather befits the former vertebra, whose tooth resembles an Axle. 1701Tauvry Anat. ii. xvi. 268 This second Vertebra has an Apophysis call'd the Tooth..The Head and the first vertebra..are qualified to turn upon that Axis. 1815Encycl. Brit. III. 289 Axis..the second vertebra of the neck; it hath a tooth which goes into the first vertebra and this tooth is by some called the axis. 1836Athenæum No. 450. 419 The Atlas and Axis of the Ichthyosaurus are united.
3. The imaginary straight line about which a body (e.g. the earth or other planet) rotates; the prolongation of that of the earth on which the heavens appear to revolve.
(The ends of the axis are poles; thence the use of axis as a line from pole to pole, or from end to end: see III.)
1549Compl. Scot. vi. 48 Ȝe sal ymagyn ane lyne that passis throucht the spere lyik til ane extree of ane cart, callit axis⁓spere. 1635N. Carpenter Geogr. Del. i. iii. 67 The motion of an iron-wire or needle..vpon his owne Axis. c1660Hobbes Physics iv. xxvi. §6. I. 428 The earth is so carried about the sun, as that its axis is thereby always kept parallel to itself. 1849M. Somerville Connex. Phys. Sc., There are at least three axes at right angles to each other round any one of which..the solid..will continue to revolve for ever.
4. a. fig. A central prop, which sustains any system (as Atlas was feigned to sustain the revolving heavens). Obs.
a1616Beaum. & Fl. Valentin. v. v, I have found out axis; You know he bears the empire. 1646Sir T. Browne Pseud. Ep. 94 The Atlas or maine axis, which supported this opinion, was daily experience.
b. fig. The relation between countries regarded as a common pivot on which they revolve; esp. the political association of 1936 (becoming in 1939 a military alliance) formed between Italy and Germany; later extended to that between Germany, Italy, and Japan; still later to that between other allied countries. Often used attrib., as Axis forces, Axis powers, and ellipt. for such phrases, with consequent pl. concord. Also transf., of any comparable association, or connecting common interest.
1936Times 3 Nov. 15/1 The ‘Rome–Berlin axis’ is a conceit which has its momentary attractions. 1938New Statesman 19 Feb. 274/2 He [sc. King Carol of Rumania] will as before try to keep one foot in the Franco-Russian camp and the other in that of the Axis Powers. 1939Times 6 Feb. 11/1 (headline) Attacks on the Axis. 1941Time 21 Apr. 34/3 The London–Washington Axis. 1942Times Weekly 7 Jan. 5 The 26 anti-Axis nations are united..in the broad conduct of the war. 1952Economist 19 July 145/1 The Moscow–Peking axis. Ibid. 22 Nov. 531/1 One [proposal] is for an Old Vic–Stratford axis, with an exchange of productions. 1959New Statesman 7 Feb. 177/1 The term ‘axis’ is looked on with disfavour here [sc. Bonn] as a reminder of the Berlin–Rome–Tokyo axis of the Nazis.
5. The geometrical line, by the revolution of a superficies about which, solids with circular section, as a globe, cylinder, cone, etc. are conceived to be generated.
(This is the axis of revolution; it coincides necessarily with the axis of symmetry; thence branch II.)
1571Digges Pantom. iii. iii. Q ij b, The Axis or Altitude of the Cone. 1796Hutton Math. Dict. I. 177 If a semi⁓circle be moved round its diameter at rest, it will generate a sphere, whose axis is that diameter.
II. Axis of symmetrical arrangement. (Cf. 5.)
6. The straight line about which the parts of a body or system are symmetrically arranged.
axis of a balance: the line upon which it turns. axis of oscillation (of a pendulum, etc.): a horizontal line passing through the centre of the oscillation, and perpendicular to its plane (Hutton 1796). axis of polarization: the central line round which the prismatic rings or curves are arranged. neutral axis (of a girder): the line where there is neither compression nor tension (Brewster).
7. Geom. Any line in a regular figure which divides it into two symmetrical parts, e.g., which joins opposite angles or the centres of opposite sides; in a conic section, the line from the principal vertex or vertices, perpendicular to the tangent at that point; in a curve, a straight line which bisects a system of parallel chords (called principal axis when it cuts them at right angles).
transverse axis (in the ellipse and hyperbola): that which passes through the two foci; conjugate axis, that which bisects the transverse one at right angles. The axes of an ellipse are also called major and minor.
1734Builder's Dict., Axis of a Conic Section, is a quiescent Right Line passing through the Middle of the Figure, and cutting all the Ordinates at Right Angles. 1796Hutton Math. Dict. I. 177 Axis..more generally..a right line conceived to be drawn from the vertex of a figure to the middle of the base. Ibid. The ellipse and hyperbola have each two axes; but the parabola has only one, and that infinite in length. Ibid. In curves of the second order, that diameter whose parallel ordinates are at right angles to it, when possible, is an Axis. 1849M. Somerville Connex. Phys. Sc. xxi. 201 Cut longitudinally, that is, parallel to the axis of the prism. 1853Sir J. Herschel Pop. Lect. Sc. iii. §13 (1873) 106 The longer axes or longest dimensions of their orbits. 1879Thomson & Tait Nat. Phil. I. i. §120.
8. Cryst. An imaginary line drawn between the centres of opposite faces or edges, or the apices of opposite angles. (See quot.)
1817R. Jameson Charac. Min. 244 Three of the cleavages are equiangular and oblique-angular, in a common axis. 1869Roscoe Elem. Chem. 192 In order to classify..crystals, the existence of certain lines within the crystal called axes is supposed, round which the form can be symmetrically built up. 1878Gurney Crystallog. 30 The straight lines or directions in the crystal which are common to two or more symmetral planes are called axes of symmetry.
9. Optics.
a. A ray passing through the centre of the eye or of a lense, or falling perpendicularly on it; the line which passes through the centres of the lenses in a telescope; the straight line from the eye to the object of sight.
1701Tauvry Anat. ii. vii. 205 To direct the two Optick axis's, in looking upon the same object. c1790J. Imison Sch. Art I. 196 If the axis of both eyes are not directed to the object, that object will appear double. 1831Brewster Optics iv. 28 In all these lenses a line..passing through the centres of their curved surfaces, and perpendicular to their plane surfaces, is called the axis. 1855H. Spencer Psychol. (1872) I. iii. x. 380 Due convergence of the visual axes. 1871J. Dicksee Perspective 27 The axis of vision or line of direction is an imaginary line proceeding from the spectator to the perspective centre.
b. axis of incidence: the line passing through the point of incidence perpendicularly to the refracting surface. axis of refraction: the continuation of the same line through the refracting medium. axis of double refraction: the line or direction on both sides of which double refraction takes place, but along which it does not exist.
1734Builder's Dict., Axis of Incidence, Refraction. 1796Hutton Math. Dict. I. 178. 1831 Brewster Optics xvii. 147 An axis of double refraction..is not like the axis of the earth, a fixed line within the rhomb or crystal. It is only a fixed direction. 1836Athenæum No. 448. 381 Like calcareous spar it has one axis of double refraction.
¶ In the three following the sense tends to pass into axis of growth or direction as in branch III.
10. Phys. and Zool. The central core of an organ or organism; the central skeleton or nervous cord; the central stem or core round which polypes grow; the central column of a whorled shell.
1741Monro Anat. Bones 54 The Powers that draw it towards the Axis of the Bone. 1830Edin. Encycl. XIV. 599 In other species, the organs, which are not in pairs, are arranged round a central axis. 1866R. Tate Brit. Mollusks iii. 44 The axis of the shell around which the whorls are coiled. 1873A. Flint Nerv. Syst. ix. 257 The nervous matter contained in the cavity..is known as the cerebro-spinal axis.
11. Bot.
a. The central column of the inflorescence or other whorl of growth.
b. The main stem and root.
1786Rees Encycl., Axis..a taper column placed in the centre of some flowers, or katkins, about which the other parts are disposed. 1835J. Comstock Yng. Botanist 239 Axis, centre of vegetation, as the pith of vascular plants. 1835Penny Cycl. III. 184 Each cluster of leaves is a small branch without perceptible axis. 1857Henfrey Bot. §42 The stem is the ascending portion of the axis. 1870Hooker Stud. Fl. 232 Erica..Seeds attached to a central axis.
12. Physiogr. and Geol. A central ridge; the central line of a valley.
anticlinal axis: the line along which two opposite planes of stratification meet in a ridge. synclinal axis: the line along which they meet in a depression.
1830Lyell Princ. Geol. I. 135 A line of volcanos..parallel to the axis of the older ridge. 1849Murchison Siluria ii. (1867) 25 These round-backed hills..rise boldly from beneath the surrounding Silurian deposits, of which they form the axis. 1854F. C. Bakewell Geol. 4 The technical name given to such a centre of elevation is the ‘anticlinal axis.’
III. A straight line from pole to pole (cf. 3), or from end to end, of any body.
13. gen. e.g. axis of the equator: the polar diameter of the earth, which is also the axis of rotation; see 3. axis of the ecliptic, axis of the horizon: a diameter of the sphere passing through these circles at right angles to their planes.
1796Hutton Math. Dict.
14. spec. An imaginary line uniting the two poles of a magnet.
1664Power Exp. Philos. iii. 158 If you divide the Magnet through a meridian, or Saw of a Segment, parallel to the Axis. 1832Nat. Philos. II. Magnetism i. §6 (U.K.S.) The straight line joining the two poles of a magnet is called its axis.
15. A main line of motion, growth, extension, direction.
1818W. Lawrence Nat. Hist. Man i. ii. (1848) 99 Its axis [of the femur] coincides with the centre of gravity of the body. 1853Kane Grinnell Exp. x. (1856) 75 The axis of Baffin's Bay..is from the north by east. Ibid. 76 The ice, after changing its original axis of drift. 1855Owen Skel. & Teeth 6 In the direction of the bone's axis. 1867A. Barry Sir C. Barry vii. 240 The principal axis of the building.
IV. Axis of reference.
16. Analyt. Geom. Each of the two intersecting straight lines, by reference to which the position of a certain point, the locus, is determined.
(Transf. from the geometrical treatment of conic sections.)
1855Todhunter Plane. Co-ord. Geom.
V. Comb. axis-cylinder (or axis-band), see quot.; attrib., as axis-ligament.
1839Todd Cycl. Anat. & Phys. III. 592/1 A central substance of nervous matter..the axis-cylinder of Rosenthal. 1855H. Spencer Psychol. (1872) I. i. ii. 27 The central fibre, or axis-cylinder of a nerve tube. 1877Rosenthal Muscles & N. 104 The axis-band, or axis-cylinder. 1877Burnett Ear 72 In all its motion as a lever the hammer swings about this axis-ligament as a fixed point.
▪ II. axis2 Zool.|ˈæksɪs|
[L., an Indian quadruped mentioned by Pliny.]
Name given by Buffon to an Indian deer (Cervus axis) known by sportsmen as the Hog-deer.
1601Holland Pliny viii. xxi. I. 206 A wild beast named Axis, with a skin like a fawn. 1774Goldsm. Nat. Hist. II. 72 The horns of the axis are round, like those of the stag. 1859Tennent Ceylon I. ii. i. 157 The spotted axis troops in herds as numerous as the fallow deer in England. |