1. [n]  male donkey
2. [n]  any of several fast-swimming predacious fishes of tropical to warm-temperate seas
3. [n]  tool for exerting pressure or lifting
4. [n]  one of four face cards in a deck bearing a picture of a young prince
5. [n]  small flag indicating a ship's nationality
6. [n]  game equipment consisting of one of several small objects picked up while bouncing a ball in the game of jacks
7. [n]  an electrical device consisting of a connector socket designed for the insertion of a plug
8. [n]  immense East Indian fruit resembling breadfruit of; its seeds are commonly roasted
9. [n]  someone who works with their hands; someone engaged in manual labor
10. [n]  a man who serves as a sailor
11. [n]  a small worthless amount; "you don't know jack"
12. [v]  hunt with a jacklight
13. [v]  lift with a jack, as of a car

Jack
The first account of JFK's life to cover the scope of his extraordinary career as well as his often troubled personal life uses hundreds of hours of previously unavailable tapes, as well as never-before-published diary entries and letters, to reveal new information about the assassinated president.

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1. \Jack\ (j[a^]k), n. [Pg. jaca, Malayalam, tsjaka.] (Bot.)
   A large tree, the {Artocarpus integrifolia}, common in the
   East Indies, closely allied to the breadfruit, from which it
   differs in having its leaves entire. The fruit is of great
   size, weighing from thirty to forty pounds, and through its
   soft fibrous matter are scattered the seeds, which are
   roasted and eaten. The wood is of a yellow color, fine grain,
   and rather heavy, and is much used in cabinetwork. It is also
   used for dyeing a brilliant yellow. [Written also {jak}.]
   

2. \Jack\, n. [F. Jacques James, L. Jacobus, Gr. ?, Heb. Ya
   'aq[=o]b Jacob; prop., seizing by the heel; hence, a
   supplanter. Cf. {Jacobite}, {Jockey}.]
   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.''
      --Chaucer.
            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 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.
      --Shak.
            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. (Zo["o]l.)
      (a) A young pike; a pickerel.
      (b) The jurel.
      (c) A large, California rock fish ({Sebastodes
          paucispinus}); -- called also {boccaccio}, and
          {m['e]rou}.
      (d) The wall-eyed pike.
   9. A drinking measure holding half a pint; also, one holding
      a quarter of a pint. [Prov. Eng.] --Halliwell.
   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}. --R. H.
           Dana, Jr.
   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} (Zo["o]l.), the whimbrel.
   {Jack frame}. (Cotton Spinning) See 4
       (g), above.
   {Jack Frost}, frost 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.
   {Jack rabbit} (Zo["o]l.), 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 ({L. 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 ({L.
      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} (Zo["o]l.), 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}. (Zo["o]l.) 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}
      ({E. 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-a-box}.
       (a) (Bot.) A tropical tree ({Hernandia sonora}), which
           bears a drupe that rattles when dry in the inflated
           calyx.
       (b) A child's toy, consisting of a box, out of which,
           when the lid is raised, a figure springs.
       (c) (Mech.) An epicyclic train of bevel gears for
           transmitting rotary motion to two parts in such a
           manner that their relative rotation may be variable;
           applied to driving the wheels of tricycles, road
           locomotives, and to cotton machinery, etc.; an
           equation box; a jack frame; -- called also
           {compensating gearing}.
       (d) A large wooden screw turning in a nut attached to the
           crosspiece of a rude press.
   {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-in-the-pulpit} (Bot.), the American plant {Aris[ae]ma
      triphyllum}, or Indian turnip, in which the upright spadix
      is inclosed.
   {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.
   {Jack-with-a-lantern}, {Jack-o'-lantern}.
       (a) An ignis fatuus; a will-o'-the-wisp. ``[Newspaper
           speculations] supplying so many more jack-o'-lanterns
           to the future historian.'' --Lowell.
       (b) A lantern made of a pumpkin so prepared as to show in
           illumination the features of a human face, etc.
   {Yellow Jack} (Naut.), the yellow fever; also, the quarantine
      flag. See {Yellow flag}, under {Flag}.
   

3. \Jack\, n. [F. jaque, jacque, perh. from the proper name
   Jacques. Cf. {Jacquerie}.]
   A coarse and cheap medi[ae]val coat of defense, esp. one made
   of leather.
         Their horsemen are with jacks for most part clad. --Sir
                                                  J. Harrington.
   

4. \Jack\, n. [Named from its resemblance to a jack boot.]
   A pitcher or can of waxed leather; -- called also {black
   jack}. [Obs.] --Dryden.
   

5. \Jack\, v. i.
   To hunt game at night by means of a jack. See 2d {Jack}, n.,
   4, n.
   

6. \Jack\, v. t.
   To move or lift, as a house, by means of a jack or jacks. See
   2d {Jack}, n., 5.
   

1. Young salmon, usually a male, that matures precociously.
2. Bank protection element consisting of wire or cable strung on three mutually perpendicular struts.