The term "Jack" has multiple meanings depending on its context.
1) In a standard deck of playing cards, Jack refers to one of four face cards (King, Queen, and two other Jacks). These are valued at 10 points each.
2) As a verb, the word can refer to lifting or moving something with a jack, such as using a car jack to lift a vehicle.
3) In some regions of England, "Jack" is used as a term of address for someone you don't know well, similar to "mate."
4) Jack is also the name of a popular alcoholic drink made from a distilled beverage and mixed with other ingredients such as fruit or cola.