jack1

noun

• 1a device for lifting heavy objects, especially one for raising the axle of a motor vehicle off the ground so that a wheel can be changed or the underside inspected.

• 2a playing card bearing a representation of a soldier, page, or knave, normally ranking next below a queen.

• 3a socket with two or more pairs of terminals, designed to receive a jack plug.

• 4 (jacks) a game played by tossing and catching small round pebbles or star-shaped pieces of metal or plastic.
• (also jackstone) a small round pebble or star-shaped piece of metal used in the game of jacks.

• 5in lawn bowling, the small ball at which the players aim.

• 6 (Jack) chiefly US informal used as a form of address to a man whose name is not known.

  [familiar form of the given name John]
• North American informal a lumberjack.
• archaic a steeplejack.
• the figure of a man striking the bell on a clock.

• 7a small version of a national flag flown at the bow of a vessel in harbor to indicate its nationality.

• 8North American informal dated money.

• 9a device for turning a spit.

• 10a part of the mechanism in a spinet or harpsichord that connects a key to its corresponding string and causes the string to be plucked when the key is pressed down.

• 11a marine fish that is typically laterally compressed with a row of large spiky scales along each side. Jacks are important in many places as food or game fish. Also called pompano, scad.

  [originally a West Indian term]

  • Family Carangidae (the jack family): many genera and numerous species. The jack family also includes the horse mackerel, pilotfish, kingfishes, and trevallies

• 12the male of some animals, especially a merlin or an ass.

• 13used in names of animals that are smaller than similar kinds, e.g., jacksnipe.

• 14short for jackrabbit.

• 15US informalshort for jack shit.