Jack
Jack could refer to:

People
Jack (20th century), inhabitant of Carbon Creek, Pennsylvania in the mid-20th century
Jack (23rd century), an ancestor of Harry Kim in the 23rd century
Jack (24th century), the genetically-engineered Human in the 24th century
Jack (card), the lowest face card in a deck of playing cards
Jack (character), a soap opera character in the late 20th century
Jack (name), a name guessed as belonging to Rumpelstiltskin 
Jack the Ripper, a killer in London, England in the late 19th century

Other references
Double-jack, a card game
Jack Daniels, sometimes shortened to "Jack"
Jack-in-the-box, a children's toy, or a hidden subroutine in a holodeck program
Jack of all trades, a handyman
Jacked, 21st century slang for being robbed

Other individuals who were identified by the given name "Jack"
 Jack Crusher, a 24th century Human
 Jack London, a 19th century Human
 Jack Nesvig, a 20th century Human

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