Forms: 3 levere, 4 levor, 4–5 levour, 6–8 leaver, 5– lever. [ME. levere, levour, a. OF. *levere, leveour (F. leveur), agent-n. f. lever to raise; in the sense ‘lever’ recorded only once (1487) as leveur; the usual Fr. word is levier (recorded from 12th c.) formed on the same vb. with different suffix; leviere fem. occurs in the 14th c.]
1. A bar of iron or wood serving to ‘prize up’ or dislodge from its position some heavy or firmly fixed object; a crowbar, handspike, or the like.
In mod. use, this sense is more or less colored by the scientific sense 2, which is alone formally recognized by Johnson.
1297. R. Glouc. (Rolls), 3103. Hii … cables vette ynowe & laddren, & leuours & uaste ssoue & drowe.
13[?]. Coer de L., 1935. Ever men bare them up with levours.
1382. Wyclif, Isa. xxvii. 1. In that dai visiten shal the Lord … vp on leuyathan, an eddere, a leuour [Vulg. serpentem vectem].
1433. Lydg., St. Edmund, III. 1202. Oon with a leuour to leffte the doore on barre.
1481. Caxton, Godfrey, clxxx. 265. Other had grete leuers and plente of ropes and Cordes.
1553. T. Wilson, Rhet. (1580), 223. An other speakes, as though his woordes had neede to bee heaved out with leavers.
1642. Fuller, Holy & Prof. St., II. xxiii. 147. Surely so heavy a log needed more levers than one.
1697. Potter, Antiq. Greece, III. xx. (1715), 148. The heavy Ship into the Sea they thrust With Leavers.
1736. Butler, Anal., I. i. 36. As carriages and leavers and scaffolds are in architecture.
1813. Scott, Rokeby, I. vi. Then clanking chains and levers tell, That o’er the moat the draw-bridge fell.
a. 1825. Forby, Voc. E. Anglia, Lewer, lower, a lever.
1881. S. H. Hodgson, Outcast Ess., 402 (Hor. Od. III. xxvi). The lever, the bright torch, the bow, For laying doors and warders low.
fig. 1831. Society, I. 230. Jealousy is a potent lever for quickening love.
1855. Motley, Dutch Rep. (1861), II. 433. The new religion was only a lever by which a few artful demagogues had attempted to overthrow the King’s authority.
† b. gen. A bar, pole or rod. Obs.
1297. R. Glouc. (Rolls), 2680. Eldol erl of gloucestre … Hente an stronge leuour.
c. 1320. Sir Beues, 1861 (MS. A). He tok a leuour in is hond, And forth to the gate he wond.
c. 1400. Ywaine & Gaw., 2386. The geant … bar a levor of yren ful strang.
c. 1530. Ld. Berners, Arth. Lyt. Bryt. (1814), 366. Gonemar helde in bothe hys handes a gret leuer, wherwith he layd on amonge those knyghtes.
1609. Bible (Douay), Numb. xiii. 24. They cutte of a branch with the grapes therof, which two men carried upon a leaver.
1613. Purchas, Pilgrimage (1614), 504. Fish-shells … so great that two strong men with a leaver can scarse draw one of them after them.
2. Mechanics. Adopted as the name for that type of ‘simple machine’ that is exemplified in the ‘lever’ (sense 1). It consists of a rigid structure of any shape (a straight bar being the normal form), fixed at one point called the fulcrum, and acted on at two other points by two forces, tending to cause it to rotate in opposite directions round the fulcrum.
The force that is regarded as intended to be resisted by the use of the lever is called the weight, and the force which is applied for this purpose is called the power. Levers are said to be of the first, second, or third kind or order according as the fulcrum, the weight or the power is in the midmost position of the three.
1648. Wilkins, Math. Mag., I. iv. 20. The second Mechanical faculty is the Leaver.
1710. J. Clarke, Rohault’s Nat. Phil. (1729), I. 43. Two Bodies hung at the Ends of a Balance or Leaver.
1803. J. Wood, Princ. Mech., iv. 50. The Lever is an inflexible rod, moveable upon a point which is called the fulcrum.
1812–6. Playfair, Nat. Phil. (1819), I. 117. Let A and B be two given weights, applied to the ends of the arms of a lever.
1829. Nat. Philos., Mechanics, II. iii. § 13. 6 (U. K. S.). If the power be in the middle, it is a lever of the third kind.
1837. Whewell, Hist. Induct. Sci. (1857), I. 186. Archimedes had established the doctrine of the lever.
1841. T. R. Jones, Anim. Kingd., 168. The levers attached to the jaws are five long and slender processes.
1851. Carpenter, Man. Phys. (ed. 2), 172. The hard envelopes … serve, like the bones of the Vertebrata, as levers by which the motor powers of the muscles are more advantageously employed.
3. Special applications. a. A roof-beam of naturally curved timber, forming one of the couples or principals supporting the roof (obs. exc. dial.). b. Steam-engine. † (a) = BEAM sb.1 11 (obs.); (b) a starting-bar. c. The piece by which the barrel of a breech-loader is opened. d. In Dentistry and Surgery = ELEVATOR 2. In Midwifery = VECTIS (Syd. Soc. Lex.). e. The first row of a fishing-net. f. Short for lever-watch.
a. 1481–2. in Charters Finchale (Surtees), p. ccclv. Pro … meremio empto pro j lever in tenemento Roberti Jakson.
b. 1758. Fitzgerald, in Phil. Trans., L. 727. The lever of the fire-engine [i.e., steam-engine] works up and down alternately.
1836. Hebert, Engin. & Mech. Encycl., II. 702. The attendant pushes the handle or lever which he holds.
c. 1881. [see lever-pin].
d. 1846. Brittan, trans. Malgaigne’s Man. Oper. Surg., 74. With the Lever.—Its extremity is passed between two teeth, a sound and the decayed one, or a sound one and a stump.
e. 1884. J. Paton, in Encycl. Brit., XVII. 359/1.
4. attrib. and Comb. a. with sense ‘belonging to a lever,’ as lever-actuation, -edge, -pin; also lever-like adj. b. with sense ‘acting as a lever, worked by a lever,’ as lever-brace, -corkscrew, -drill, -hoist, -jack, -knife, -pallet, -pendulum, -press, -punch, -shears, -spar, -valve.
1889. G. Findlay, Eng. Railway, 79. The frame … known as *lever actuation.
1860. All Year Round, No. 57. 162. The *lever corkscrew gave a zest to his wine.
1884. F. J. Britten, Watch & Clockm., 207. *Lever Edges … are polished in a swing tool.
1867. J. Macgregor, Voy. Alone, 41. The pantry is beside them, with … pepper … mustard, corkscrew, and *lever-knife for preserved meat tins, &c., &c.
1891. Atkinson, Last of Giant Killers, 190. The steel point of Sir Jack’s Staff was inserted beneath it, and *lever-like pressure applied.
1825. J. Nicholson, Operat. Mechanic, 524. The centre of the *lever-pallet … is in a right line between the centre of the scape-wheel and the centre of the verge. Ibid., 526. In Ellicott’s pendulum the ball was adjustable by levers, thence called the *lever-pendulum.
1881. Greener, Gun, 263. Next turn out the lever pin on top of lever.
1873. W. Cory, Lett. & Jrnls. (1897), 316. The *lever-spar of a water-lift.
5. Special combs.: lover-beam Steam-engine (see BEAM sb.1 11); lever-board, -bridge (see quots.); lever-engine, † (a) = beam-engine (obs.); (b) = side-lever engine (1876 in Knight, Dict. Mech. and in later Dicts.); lever escapement (Watchmaking), an escapement in which the connection between the pallet and the balance is made by means of two levers, one attached to the pallets and the other to the balance staff (Britten); lever-fly, a punching machine worked by a fly-wheel and a lever; lever-frame U.S., ‘in a railroad hand-car, a wooden frame shaped somewhat like a letter A, which supports the lever-shaft and lever on the platform’ (Cent. Dict.); lever-man U.S., one employed to work the levers in a railway signal-box; lever watch, a watch with a lever escapement; lever-wood, the Virginian hop-hornbeam or ironwood, Ostrya Virginica (Treas. Bot., 1866).
1824. R. Stuart, Hist. Steam Engine, 159. As the *lever-beam was dismissed, he communicated the motion to the paddle-wheels by a rod and crank attached to the piston.
1823. P. Nicholson, Pract. Build., 587. *Lever-boards, a set of boards, parallel to each other, so connected together that they may be turned to any angle, for the admission of more or less air or light; or so as to lap upon each other and exclude both.
1853. Sir H. Douglas, Milit. Bridges, 312. That which is called a *Lever Bridge is made by cutting down trees, and sinking the buts of them in the bank on each side sufficiently deep that the parts which are buried may exceed in weight those which are out of the ground.
1744. Desaguliers, Experim. Philos., II. 489. The *Leaver Engine, often call’d Newcomen’s.
1838. Penny Cycl., XII. 303/2. *Lever-escapement.
1884. F. J. Britten, Watch & Clockm., 141. The Lever Escapement … is generally preferred for pocket watches.
1831. J. Holland, Manuf. Metal, I. 131. The holes … are punched in the metal by the assistance of what the boiler makers call a *lever fly.
1901. Daily News, 12 Jan., 6/2. A saving … has been effected in the wages of *lever men.
1848. Chambers’s Inform., I. 285/2. The *lever watch is so named from the lever escapement of Mudge.
