Jack n.
 1. A familiar nickname of, or substitute for, John.
    You are John Rugby, and you are Jack Rugby.   --Shak.
 2. An impertinent or silly fellow; a simpleton; a boor; a clown; also, a servant; a rustic. “Jack fool.”
 Since every Jack became a gentleman,
 There 's many a gentle person made a Jack.   --Shak.
 3. A popular colloquial name for a sailor; -- called also Jack tar, and Jack afloat.
 4. A mechanical contrivance, an auxiliary machine, or a subordinate part of a machine, rendering convenient service, and often supplying the place of a boy or attendant who was commonly called Jack; as: (a) A device to pull off boots. (b) A sawhorse or sawbuck. (c) A machine or contrivance for turning a spit; a smoke jack, or kitchen jack. (b) Mining A wooden wedge for separating rocks rent by blasting. (e) Knitting Machine A lever for depressing the sinkers which push the loops down on the needles. (f) Warping Machine A grating to separate and guide the threads; a heck box. (g) Spinning A machine for twisting the sliver as it leaves the carding machine. (h) A compact, portable machine for planing metal. (i) A machine for slicking or pebbling leather. (k) A system of gearing driven by a horse power, for multiplying speed. (l) A hood or other device placed over a chimney or vent pipe, to prevent a back draught. (m) In the harpsichord, an intermediate piece communicating the action of the key to the quill; -- called also hopper. (n) In hunting, the pan or frame holding the fuel of the torch used to attract game at night; also, the light itself.  --C. Hallock.
 5. A portable machine variously constructed, for exerting great pressure, or lifting or moving a heavy body such as an automobile through a small distance. It consists of a lever, screw, rack and pinion, hydraulic press, or any simple combination of mechanical powers, working in a compact pedestal or support and operated by a lever, crank, capstan bar, etc. The name is often given to a jackscrew, which is a kind of jack.
 6. The small bowl used as a mark in the game of bowls.
    Like an uninstructed bowler who thinks to attain the jack by delivering his bowl straight forward upon it.   --Sir W. Scott.
 7. The male of certain animals, as of the ass.
 8. Zool. (a) A young pike; a pickerel. (b) The jurel. (c) A large, California rock fish (Sebastodes paucispinus); -- called also boccaccio, and mérou. (d) The wall-eyed pike.
 9. A drinking measure holding half a pint; also, one holding a quarter of a pint. [Prov. Eng.]
 10. Naut. (a) A flag, containing only the union, without the fly, usually hoisted on a jack staff at the bowsprit cap; -- called also union jack. The American jack is a small blue flag, with a star for each State. (b) A bar of iron athwart ships at a topgallant masthead, to support a royal mast, and give spread to the royal shrouds; -- called also jack crosstree.
 11. The knave of a suit of playing cards.
 Note: ☞ Jack is used adjectively in various senses. It sometimes designates something cut short or diminished in size; as, a jack timber; a jack rafter; a jack arch, etc.
 Jack arch, an arch of the thickness of one brick.
 Jack back Brewing & Malt Vinegar Manuf., a cistern which receives the wort. See under 1st Back.
 Jack block Naut., a block fixed in the topgallant or royal rigging, used for raising and lowering light masts and spars.
 Jack boots, boots reaching above the knee; -- worn in the 17 century by soldiers; afterwards by fishermen, etc.
 Jack crosstree. Naut. See 10, b, above.
 Jack curlew Zool., the whimbrel.
 Jack frame. Cotton Spinning See 4 (g), above.
 Jack Frost, frost or cold weather personified as a mischievous person.
 Jack hare, a male hare. --Cowper.
 Jack lamp, a lamp for still hunting and camp use. See def. 4 (n.), above.
 Jack plane, a joiner's plane used for coarse work.
 Jack post, one of the posts which support the crank shaft of a deep-well-boring apparatus.
 Jack pot Poker Playing, the name given to the stakes, contributions to which are made by each player successively, till such a hand is turned as shall take the “pot,” which is the sum total of all the bets.  See also jackpot.
 Jack rabbit Zool., any one of several species of large American hares, having very large ears and long legs. The California species (Lepus Californicus), and that of Texas and New Mexico (Lepus callotis), have the tail black above, and the ears black at the tip. They do not become white in winter. The more northern prairie hare (Lepus campestris) has the upper side of the tail white, and in winter its fur becomes nearly white.
 Jack rafter Arch., in England, one of the shorter rafters used in constructing a hip or valley roof; in the United States, any secondary roof timber, as the common rafters resting on purlins in a trussed roof; also, one of the pieces simulating extended rafters, used under the eaves in some styles of building.
 Jack salmon Zool., the wall-eyed pike, or glasseye.
 Jack sauce, an impudent fellow. [Colloq. & Obs.]
 Jack shaft Mach., the first intermediate shaft, in a factory or mill, which receives power, through belts or gearing, from a prime mover, and transmits it, by the same means, to other intermediate shafts or to a line shaft.
 Jack sinker Knitting Mach., a thin iron plate operated by the jack to depress the loop of thread between two needles.
 Jack snipe. Zool. See in the Vocabulary.
 Jack staff Naut., a staff fixed on the bowsprit cap, upon which the jack is hoisted.
 Jack timber Arch., any timber, as a rafter, rib, or studding, which, being intercepted, is shorter than the others.
 Jack towel, a towel hung on a roller for common use.
 Jack truss Arch., in a hip roof, a minor truss used where the roof has not its full section.
 Jack tree. Bot. See 1st Jack, n.
 Jack yard Naut., a short spar to extend a topsail beyond the gaff.
 Blue jack, blue vitriol; sulphate of copper.
 Hydraulic jack, a jack used for lifting, pulling, or forcing, consisting of a compact portable hydrostatic press, with its pump and a reservoir containing a supply of liquid, as oil.
 Jack-at-a-pinch. (a) One called upon to take the place of another in an emergency. (b) An itinerant parson who conducts an occasional service for a fee.
 Jack-at-all-trades, one who can turn his hand to any kind of work.
 Jack-by-the-hedge Bot., a plant of the genus Erysimum (Erysimum alliaria, or Alliaria officinalis), which grows under hedges. It bears a white flower and has a taste not unlike garlic. Called also, in England, sauce-alone. --Eng. Cyc.
 Jack-in-office, an insolent fellow in authority. --Wolcott.
 Jack-in-the-bush Bot., a tropical shrub with red fruit (Cordia Cylindrostachya).
 Jack-in-the-green, a chimney sweep inclosed in a framework of boughs, carried in Mayday processions.
 Jack-of-the-buttery Bot., the stonecrop (Sedum acre).
 Jack-of-the-clock, a figure, usually of a man, on old clocks, which struck the time on the bell.
 Jack-on-both-sides, one who is or tries to be neutral.
 Jack-out-of-office, one who has been in office and is turned out. --Shak.
 Jack the Giant Killer, the hero of a well-known nursery story.
 Yellow Jack Naut., the yellow fever; also, the quarantine flag. See Yellow flag, under Flag.
 Jack·ass n.
 1. The male ass; a donkey.
 2. A conceited dolt; a perverse blockhead; -- disparaging and offensive.
 Jackass bark Naut., a three-masted vessel, with only the foremast square-rigged; a barkentine.
 Jackass deer Zool., the koba.
 Jackass hare, Jackass rabbit Zool.. See Jack rabbit, under 2d Jack, n.
 Jackass penguin Zool., any species of penguin of the genus Spheniscus, of which several are known.  One species (Spheniscus demersus) inhabits the islands near the Cape of Good Hope; another (Spheniscus Magellanicus) is found at the Falkland Islands. They make a noise like the braying of an ass; -- hence the name.
 Laughing jackass. Zool. See under Laughing.
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 Prai·rie n.
 1. An extensive tract of level or rolling land, destitute of trees, covered with coarse grass, and usually characterized by a deep, fertile soil. They abound throughout the Mississippi valley, between the Alleghanies and the Rocky mountains.
 From the forests and the prairies,
 From the great lakes of the northland.   --Longfellow.
 2. A meadow or tract of grass; especially, a so called natural meadow.
 Prairie chicken Zool., any American grouse of the genus Tympanuchus, especially Tympanuchus Americanus (formerly Tympanuchus cupido), which inhabits the prairies of the central United States. Applied also to the sharp-tailed grouse.
 Prairie clover Bot., any plant of the leguminous genus Petalostemon, having small rosy or white flowers in dense terminal heads or spikes. Several species occur in the prairies of the United States.
 Prairie dock Bot., a coarse composite plant (Silphium terebinthaceum) with large rough leaves and yellow flowers, found in the Western prairies.
 Prairie dog Zool., a small American rodent (Cynomys Ludovicianus) allied to the marmots. It inhabits the plains west of the Mississippi. The prairie dogs burrow in the ground in large warrens, and have a sharp bark like that of a dog. Called also prairie marmot.
 Prairie grouse. Same as Prairie chicken, above.
 Prairie hare Zool., a large long-eared Western hare (Lepus campestris). See Jack rabbit, under 2d Jack.
 Prairie hawk, Prairie falcon Zool., a falcon of Western North America (Falco Mexicanus). The upper parts are brown. The tail has transverse bands of white; the under parts, longitudinal streaks and spots of brown.
 Prairie hen. Zool. Same as Prairie chicken, above.
 Prairie itch Med., an affection of the skin attended with intense itching, which is observed in the Northern and Western United States; -- also called swamp itch, winter itch.
 Prairie marmot. Zool. Same as Prairie dog, above.
 Prairie mole Zool., a large American mole (Scalops argentatus), native of the Western prairies.
 Prairie pigeon, Prairie plover, or Prairie snipe Zool., the upland plover. See Plover, n., 2.
 Prairie rattlesnake Zool., the massasauga.
 Prairie snake Zool., a large harmless American snake (Masticophis flavigularis). It is pale yellow, tinged with brown above.
 Prairie squirrel Zool., any American ground squirrel of the genus Spermophilus, inhabiting prairies; -- called also gopher.
 Prairie turnip Bot., the edible turnip-shaped farinaceous root of a leguminous plant (Psoralea esculenta) of the Upper Missouri region; also, the plant itself. Called also pomme blanche, and pomme de prairie.
 Prairie warbler Zool., a bright-colored American warbler (Dendroica discolor). The back is olive yellow, with a group of reddish spots in the middle; the under parts and the parts around the eyes are bright yellow; the sides of the throat and spots along the sides, black; three outer tail feathers partly white.
 Prairie wolf. Zool. See Coyote.
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 Rab·bit n.  Zool. Any of the smaller species of the genus Lepus, especially the common European species (Lepus cuniculus), which is often kept as a pet, and has been introduced into many countries. It is remarkably prolific, and has become a pest in some parts of Australia and New Zealand.
 Note: ☞ The common American rabbit (Lepus sylvatica) is similar but smaller. See Cottontail, and Jack rabbit, under 2d Jack. The larger species of Lepus are commonly called hares. See Hare.
 Angora rabbit Zool., a variety of the domestic rabbit having long, soft fur.
 Rabbit burrow, a hole in the earth made by rabbits for shelter and habitation.
 Rabbit fish. Zool. (a) The northern chimaera (Chimaera monstrosa). (b) Any one of several species of plectognath fishes, as the bur fish, and puffer. The term is also locally applied to other fishes.
 Rabbits' ears. Bot. See Cyclamen.
 Rabbit warren, a piece of ground appropriated to the breeding and preservation of rabbits. --Wright.
 Rock rabbit. (a) Zool. See Daman, and Klipdas. (b) the pika.
 Welsh rabbit, a dish of which the chief constituents are melted cheese over toasted bread, flavored in various ways, as with ale, beer, milk, or spices. The name is popularly said to be a corruption of Welsh rare bit, but it is probably merely a humorous designation; -- also called Welsh rarebit.
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