Le·ver n.
 1. Mech. A rigid piece which is capable of turning about one point, or axis (the fulcrum), and in which are two or more other points where forces are applied; -- used for transmitting and modifying force and motion. Specif., a bar of metal, wood, or other rigid substance, used to exert a pressure, or sustain a weight, at one point of its length, by receiving a force or power at a second, and turning at a third on a fixed point called a fulcrum. It is usually named as the first of the six mechanical powers, and is of three kinds, according as either the fulcrum F, the weight W, or the power P, respectively, is situated between the other two, as in the figures.
 2. Mach. (a) A bar, as a capstan bar, applied to a rotatory piece to turn it. (b) An arm on a rock shaft, to give motion to the shaft or to obtain motion from it.
 Compound lever, a machine consisting of two or more levers acting upon each other.
 Lever escapement. See Escapement.
 Lever jack. See Jack, n., 5.
 Lever watch, a watch having a vibrating lever to connect the action of the escape wheel with that of the balance.
 Universal lever, a machine formed by a combination of a lever with the wheel and axle, in such a manner as to convert the reciprocating motion of the lever into a continued rectilinear motion of some body to which the power is applied.
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 Watch n.
 1. The act of watching; forbearance of sleep; vigil; wakeful, vigilant, or constantly observant attention; close observation; guard; preservative or preventive vigilance; formerly, a watching or guarding by night.
    Shepherds keeping watch by night.   --Milton.
    All the long night their mournful watch they keep.   --Addison.
 Note: ☞ Watch was formerly distinguished from ward, the former signifying a watching or guarding by night, and the latter a watching, guarding, or protecting by day Hence, they were not unfrequently used together, especially in the phrase to keep watch and ward, to denote continuous and uninterrupted vigilance or protection, or both watching and guarding. This distinction is now rarely recognized, watch being used to signify a watching or guarding both by night and by day, and ward, which is now rarely used, having simply the meaning of guard, or protection, without reference to time.
    Still, when she slept, he kept both watch and ward.   --Spenser.
    Ward, guard, or custodia, is chiefly applied to the daytime, in order to apprehend rioters, and robbers on the highway . . .  Watch, is properly applicable to the night only, . . . and it begins when ward ends, and ends when that begins.   --Blackstone.
 2. One who watches, or those who watch; a watchman, or a body of watchmen; a sentry; a guard.
    Pilate said unto them, Ye have a watch; go your way, make it as sure as ye can.   --Matt. xxvii. 65.
 3. The post or office of a watchman; also, the place where a watchman is posted, or where a guard is kept.
 He upbraids Iago, that he made him
 Brave me upon the watch.   --Shak.
 4. The period of the night during which a person does duty as a sentinel, or guard; the time from the placing of a sentinel till his relief; hence, a division of the night.
    I did stand my watch upon the hill.   --Shak.
 Might we but hear . . .
 Or whistle from the lodge, or village cock
 Count the night watches to his feathery dames.   --Milton.
 5. A small timepiece, or chronometer, to be carried about the person, the machinery of which is moved by a spring.
 Note: ☞ Watches are often distinguished by the kind of escapement used, as an anchor watch, a lever watch, a chronometer watch, etc. (see the Note under Escapement, n., 3); also, by the kind of case, as a gold or silver watch, an open-faced watch, a hunting watch, or hunter, etc.
 6. Naut. (a) An allotted portion of time, usually four hour for standing watch, or being on deck ready for duty.   Cf. Dogwatch.  (b) That part, usually one half, of the officers and crew, who together attend to the working of a vessel for an allotted time, usually four hours. The watches are designated as the port watch, and the starboard watch.
 Anchor watch Naut., a detail of one or more men who keep watch on deck when a vessel is at anchor.
 To be on the watch, to be looking steadily for some event.
 Watch and ward Law, the charge or care of certain officers to keep a watch by night and a guard by day in towns, cities, and other districts, for the preservation of the public peace. --Wharton.  --Burrill.
 Watch and watch Naut., the regular alternation in being on watch and off watch of the two watches into which a ship's crew is commonly divided.
 Watch barrel, the brass box in a watch, containing the mainspring.
 Watch bell Naut., a bell struck when the half-hour glass is run out, or at the end of each half hour. --Craig.
 Watch bill Naut., a list of the officers and crew of a ship as divided into watches, with their stations. --Totten.
 Watch case, the case, or outside covering, of a watch; also, a case for holding a watch, or in which it is kept.
 Watch chain. Same as watch guard, below.
 Watch clock, a watchman's clock; see under Watchman.
 Watch fire, a fire lighted at night, as a signal, or for the use of a watch or guard.
 Watch glass. (a) A concavo-convex glass for covering the face, or dial, of a watch; -- also called watch crystal. (b) Naut. A half-hour glass used to measure the time of a watch on deck.
 Watch guard, a chain or cord by which a watch is attached to the person.
 Watch gun Naut., a gun sometimes fired on shipboard at 8 p. m., when the night watch begins.
 Watch light, a low-burning lamp used by watchers at night; formerly, a candle having a rush wick.
 Watch night, The last night of the year; -- so called by the Methodists, Moravians, and others, who observe it by holding religious meetings lasting until after midnight.
 Watch paper, an old-fashioned ornament for the inside of a watch case, made of paper cut in some fanciful design, as a vase with flowers, etc.
 Watch tackle Naut., a small, handy purchase, consisting of a tailed double block, and a single block with a hook.