(jak) noun
1. Mech. a A device, appliance, or part of a machine: so called from its serving to supply the place of an assistant, b A portable device, operating by lever, screw, or other mechanical principle, for exerting considerable energy through a short distance: used in raising weights.
2. The male of the ass or of certain other animals.
3. A flag showing the canton or union of the national ensign without the fly, as of the United States or of Great Britain. See UNION JACK.
4. A playing card; in most games, the lowest of the face cards; a knave.
5. U.S. Slang Money.
6. Electr. A spring clip to which the wires of a circuit may be attached and which is arranged for the insertion of a plug.
7. A bootjack.
8. A jacklight.
9. A device to prevent back draft in a chimney or vent pipe.
10. Naut. An iron crosstree at the topgallant-masthead: also jack crosstree.
11. An automatic figure of a man which strikes the time bell of a clock.
12. A small white ball used as the object played for in the game of bowls.
13. The hopper of a pianoforte; in a harpsichord, the piece of wood holding the quill which strikes the string.
14. One of various fishes, as a pike or pickerel.
15. plural The game played with jackstones.
—hydraulic jack A device for lifting heavy weights or exerting great force by fluid pressure from a hand pump connected with a large–bore cylinder and a piston: also hydrostatic jack.
—v.t.
1. To raise or lift with or as with a jack.
2. Colloq. To advance, as a price or charge: often with up.
3. U.S. To jack–light. [from Jack, a personal name]

(jak) noun
1. A cultivated tree (Artocarpus heterophyllus) of SE Asia, resembling the breadfruit tree.
2. Its yellow wood, furnishing valuable lumber.
3. The large fruit, resembling the breadfruit, produced by this tree. [<Pg. jaca <Malayalam chakka]

(jak) noun
A medieval coat of mail made of two thicknesses of leather or cloth and padded; a gambeson. [<OF jacque <Sp. jaco,? <Arabic shakk]

(jak)
1. A nickname for JOHN; earlier, for JAMES, as derived from JACOB.
2. Hence, from its frequency, a man; fellow; especially, a sailor; also, a handy man for odd jobs: in these senses usually jack. [<OF Jacques Jacob]