| 释义 |
constant, a. (n.)|ˈkɒnstənt|
[a. F. constant (14th c. in Littré), ad. L. constāns, constānt-em standing firm, firm, immovable, stable, etc., pres. pple. (also used as adj.) of constāre to stand together, stand firm, etc., f. con- + stāre to stand.]
A. adj.
1. a. Standing firm in mind or purpose; steadfast, unmoved, resolute. In later use, with a descriptive n., as martyr, student, etc., or with mind.
c1386Chaucer Clerk's T. 991 She ay sad and constant as a wal, Continuynge euere hire Innocence oueral. 1483Caxton Cato A viij, He ought to be vertuous constant and stedfast. 1655–60Stanley Hist. Philos. (1701) 3/2 These things..which thus disorder even thee a most constant person. 1671Milton Samson 848 The best-resolved of men, The constantest.
1562(title), Certayn Godly Sermons made upon the Lords Prayer, preached by the Righte Reuerende Father and constant Martyr of Christ, Master Hughe Latimer. 1614Bp. Hall Medit. & Vowes iii. §78 The constant suffrings of ancient martyrs. 1667Milton P.L. v. 902 Nor number, nor example with him wrought To swerve from truth, or change his constant mind. 1669Penn No Cross i. v. §5 Stephen, that bold and constant Martyr of Jesus. 1749Fielding Tom Jones viii. xviii, Which might have affected a more constant mind than that of Mr. Partridge. 1859Sat. Rev. VIII. 726 The most constant enemy of their revolutionary..principles.
†b. Const. to do something. Obs.
1481Caxton Myrr. i. iv. 13 Prudent and constaunt for to doo weel and prouffyt. 1535Coverdale 1 Chron. xxix [xxviii]. 7 Yf he be constant to do after my commaundementes. 1602Marston Ant. & Mel. ii. Wks. 1856 I. 26 O no, thart too constant to afflict my heart.
2. Steadfast in attachment to a person or cause; faithful, true (to).
c1425Wyntoun Cron. ix. xxvi. 63 He wes a constant Catholike, All Lollard he hatyt and Heretike. 1599Shakes. Much Ado ii. iii. 67 Men were deceiuers euer..To one thing constant neuer. 1606Wily Beguilde in Hazl. Dodsley IX. 315 And I as constant as Penelope. c1665Mrs. Hutchinson Mem. Col. Hutchinson (1846) 29 Faithful and constant to his friends. 1702Pope Jan. & May 41 Tho' fortune change, his constant spouse remains. 1887Lowell Democr. 93 Surely there are no friends so constant as the poets.
†3.
a. Firm in opinion, certain, confident.
b. Of a statement, etc.: Certain. It is constant = L. constat.
1601Shakes. Twel. N. iv. ii. 53, I am no more madde then you are, make the triall of it in any constant question. 1611B. Jonson Catiline i. i. 267 The augurs all are constant I am meant. 1626Massinger Rom. Actor v. ii, Predictions! I grow constant they are false. 1667Sir W. Temple Let. 27 May Wks. (1720) II. 35 It is constant, without any dispute, that if they had fallen on these provinces in the beginning of this month, Charleroy, etc...would have cost them neither time nor danger.
4. a. Of things: Remaining ever the same in condition, quality, state, or form; invariable, fixed, unchanging, uniform.
Often used with a noun of quality, where constantly with the corresponding adj. might be used; e.g. constant fatality, the quality of being constantly, or in all cases, fatal.
1549Compl. Scot. i. 21 Na thyng remanis lang constant in ane prosperus stait. 1597Hooker Eccl. Pol. v. lxxi. §2 The constant habit of well-doing. 1627–47Feltham Resolves i. ix. (1677) 12 Time keeps his constant pace. 1651Hobbes Leviath. iii. xxxiv. 207 The foundation of all true Ratiocination, is the constant Signification of words. 1684Contempl. State Man i. ii. (1699) 17 Nothing here below is constant, but all is mutable. 1710Berkeley Princ. Hum. Knowl. §150 This is the constant language of Scripture. 1728Veneer Sincere Penit. Ded., Your constant way both of thinking and living. 1807Med. Jrnl. XVII. 572 The constant fatality of small-pox at that age. 1833Lyell Princ. Geol. III. 161 The sand is frequently yellow..but this colour is by no means constant. 1860Tyndall Glac. i. i. 1 This direction remained perfectly constant throughout the entire quarry.
†b. Unvaried, not changed; invariably used.
c1710C. Fiennes Diary (1888) 216 This is y⊇ Constant way all people goe, and saved severall miles ridings. Ibid. 239 The kings Constant bed Chamber. 1711Addison Spect. No. 129 ⁋1 Did they keep to one constant Dress they would sometimes be in the Fashion. 1830D'Israeli Chas. I, III. vi. 92 The King had his constant hours for writing, and he read much.
c. Nat. Hist. Having one unvarying form or type.
1793W. Curtis in Bot. Mag. I. 183 Who ever saw its leaves constant in their form? 1876Darwin in Life & Lett. (1887) I. 90 Keeping specific forms constant.
d. Invariable in presence or occurrence.
1817Ld. Loughborough in Douglass Rep. II. 727 A fine to be paid on the change of a tenant is almost a constant incident of a copyhold estate. 1839G. Bird. Nat. Phil. 330 The line D [of the spectrum]..appears to be very constant in the planets, and in many..fixed stars. 1875W. Houghton Brit. Insects 18 The evacuating ducts are constant.
†e. constant age: see consistent 2 b. Obs.
1620Venner Via Recta (1650) 291 Next is the constant and manly age to the fiftieth year.
f. constant white, = permanent white (see permanent a. 1 d).
1854F. W. Fairholt Dict. Terms Art 127 Constant white, permanent white, a pigment prepared from the sulphate of barytes, useful in water-colour painting, and possessing great body. 1886[see baryta white s.v. baryta]. 1951R. Mayer Artist's Hand-Bk. ii. 48 Constant white, blanc fixe.
5. Math. and Phys.
a. Remaining the same in quantity or amount under uniform conditions; retaining the same value throughout an investigation or process. Opposed to variable.
1753Chambers Cycl. Supp. s.v., The semi-diameter of a circle is a constant quantity; for while the absciss and semi-ordinates increase, it remains the same. 1756N. Saunderson Meth. Fluxions 2 The Fluxion of a constant Quantity is nothing. 1803J. Wood Princ. Mech. i. 15 When a force..acts incessantly, it is called a constant force. 1830Lyell Princ. Geol. I. 113 However constant we believe the relative proportion of sea and land to continue. 1871B. Stewart Heat 24 If we imagine the bore of the tube to preserve a constant volume for all temperatures.
b. In various Combs. (used chiefly attrib. with hyphen), as constant current, constant frequency, constant mesh, constant speed, constant velocity, constant voltage.
1904Goodchild & Tweney Technol. & Sci. Dict. 126/1 *Constant current, a current whose amount or value is allowed to vary as little as possible. 1934Discovery Nov. 324/2 D.C. to A.C. rotary converters,..constant current charging dynamos and an entirely portable petrol-driven alternator. 1962Simpson & Richards Junction Transistors vii. 156 The currents I′b1 and Ib2 may reach considerably higher values than those obtainable with constant-current drive.
1935Discovery Nov. 325/1 Some lengths of *constant frequency film of known accuracy were obtained. 1940Chambers's Techn. Dict. 191/2 Constant-frequency oscillator, an oscillator in which special precautions are taken to ensure that the frequency remains constant. 1956Nature 10 Mar. 470/2 The accelerated electrons can stay in phase with the constant-frequency accelerating voltage.
1924A. W. Judge Mod. Motor Cars II. iii. 54 (heading) *Constant mesh gears. 1967Economist 8 July p. xxx/1 Better drivers still prefer the cruder ‘constant mesh’ gearboxes where each gear is engaged by a small clutch and which needs a surer touch. Constant mesh has a lighter action and more positive and direct ‘feel’ than the more complex synchromesh.
1937Jrnl. R. Aeronaut. Soc. XLI. 146 Charts for Calculating the Performance of Airplanes having *Constant Speed Propellers. 1938Encycl. Brit. Bk. of Yr. 79/2 The variable pitch and especially the constant-speed airscrew have become a necessity for reasonable take-offs.
1935Discovery Sept. 278/1 With *constant velocity scanning, the successive signal strengths are proportioned to the corresponding light and shade areas of the image focused by the lens upon the mosaic. 1966Times 18 Mar. 6/7 The constant velocity joints of an M.G. 1100 car he examined after it had been involved in a fatal accident were perfect.
1904Goodchild & Tweney Technol. & Sci. Dict. 126/1 *Constant voltage, an electrical pressure or voltage kept at a uniform value. 1959‘Motor’ Man. (ed. 36) vi. 156 The so-called constant-voltage system..has been widely adopted during the past few years.
6. a. Of actions, conditions, processes, etc.: Continuing without intermission or cessation, or only with such intermissions as do not interrupt continuity; continual, incessant, perpetual, persistent.
1653Walton Angler 163 By reason of..the Owners constant being neer to them. 1688Col. Rec. Pennsylv. I. 239 Not able to bear y⊇ Charge of Constant Attendance. a1763Shenstone Wks. (1764) I. 66 By constant vigils worn. 1830Lyell Princ. Geol. I. 117 In a state of constant and universal flux and reflux. 1869E. A. Parkes Pract. Hygiene (ed. 3) 12 The supply of water to houses may be..intermittent or constant. 1890Sir N. Lindley in Law Times Rep. LXIII. 690/1 Forms..in constant use in the Chancery Division. Mod. The constant ticking of a watch. Disturbed by their constant chatter. The constant repetition of this expression.
†b. Of a thing: Always kept up; permanent.
1620–55I. Jones Stone-Heng. (1725) 6 There were then no publick Roads..no constant Habitations. 1645Fuller Good Th. in Bad T. (1841) 20 No guest comes unawares to him who keeps a constant table. c1710C. Fiennes Diary (1888) 1 A large Cross..and house over it for a Constant Market for fruite, etc. 1818Cruise Digest (ed. 2) III. 152 The appellation of curia regis was only applied to that constant and permanent court..held in the king's palace.
c. transf. Of a person: Continually engaged in the action denoted by the noun (or by the context).
1639Fuller Holy War v. xiii. (1840) 265 The German emperor..was not constant amongst them. 1649Milton Eikon. Wks. 1738 I. 368 A constant reader of Saint Paul's Epistles. 1712Steele Spect. No. 430 ⁋1 Each Beggar that is constant at a particular Place. 1872E. Peacock Mabel Heron I. ix. 167 He was her constant adviser. 1876J. H. Newman Hist. Sk. II. i. viii. 159 He was constant in devotional and penitential exercises.
d. constant attendance allowance, formerly, the official name for attendance allowance (s.v. attendance 11), orig. payable to persons disabled as a result of injury at work.
1945Hansard Commons 10 Oct. 278 An additional allowance of up to {pstlg}1 a week may be paid if constant attendance is required. This will be paid even if the necessary care is given by the injured worker's wife... If a pensioner has to enter hospital..however..the constant attendance allowance will cease for that period. 1967Ibid. 4 Dec. 941 (heading) Constant attendance allowance.
†7. Settled, firm, steady (physically). Obs.
1596Dalrymple tr. Leslie's Hist. Scot. ii. (1887) 156 Ane oratione sa excellent and elegant, wt sa constante a countenance. 1610Shakes. Temp. ii. ii. 119 'Prethee doe not turne me about, my stomacke is not constant. 1741Betterton Hist. Eng. Stage v. 69 A constant and direct Foot, is the Index, of a steady, certain, constant..Study and Aim.
†8. Consistent, consonant (to). Obs.
1580Baret Alv. C. 1107 A death constant and agreeable to a life honestly and godly ledde.
†9. Of firm or solid consistency. Obs. rare.
a1691Boyle Hist. Firmness (J.), Mix them, you may turn these two fluid liquors into a constant body.
B. n. Math. and Physics. A quantity which does not vary, or which is assumed not to vary, throughout an investigation: opposed to variable.
Often applied to a numerical quantity expressing the fixed relation between two elements, geometrical or physical, the effect of some constant force or motion, or combination of forces or motions, or the value of some particular physical property of a substance, that remains always the same for the same substance in the same conditions, but differs for different substances: thus circular constant, constant of aberration, friction, gravitation, nutation, precession, constants of colour, tidal constants, etc.
1832W. Turnbull (title), Treatise on Strength, Flexure, and Stiffness of Cast-Iron Beams and Columns, with Tables of Constants. 1837Penny Cycl. VII. 469 The proportion between the circumference and diameter of a circle is a determinate constant. 1869T. L. Phipson tr. Guillemin's The Sun (1870) 27 A constant quantity of heat, which Pouillet has named the Solar constant, because it expresses the constant heating power of the Sun. 1879O. N. Rood Chromatics xiv. 210 Its colour depends, then, on its luminosity, wave⁓length, and purity; these quantities..are called the constants of colour. 1886Whitaker's Almanack, Tidal Constants, The time of High Water at the undermentioned Ports and Places may be approximately found by taking the time of High Water at London Bridge, and adding to or subtracting therefrom the quantities annexed. 1890C. A. Young Elem. Astron. §126 The velocity of light being 186,330 miles per second..while that of the earth in its orbit is 18·5 miles, we find that a star, situated on a line at right angles to the direction of the earth's motion, is apparently displaced by an angle which equals..20{pp}·5..This is the so-called ‘Constant of Aberration’. Ibid. §211 The Solar Constant is the number of heat units which a square unit of the earth's surface, unprotected by any atmosphere, and exposed perpendicularly to the sun's rays, would receive from the sun in a unit of time.
fig.1856Emerson Eng. Traits, Lit. Wks. (Bohn) II. 107 A few generalizations..are in the world constants, like the Copernican and Newtonian theories in physics. 1865J. Martineau in Theolog. Rev. 670 What he regards as the constants of religion. |