A highly useful word with many meanings
1) a man's first name, either as a shortened version of Jackson or as a nickname for John/Jon
2) a shortened version of jack-ass, as a way to avoid swearing
3) a substitute for the word shit, another way to avoid swearing
4) a nickname for a baseball home run
5) the nickname for Jack Daniel's Whiskey
6) a type of card in a standard deck
7) slang for stealing/ripping off, probably derived from the work 'hijack'
8) slang for excitement
9) slang for a beating
10) a nickname for money, popularized by the movie 'New Jack City'
1) Jack London was a famous author.
2) "Stop making jokes and be serious, Larry. Don't be such a jack."
3) "Keith, stop acting like you understand. You don't know jack about what's going on with me and Emily."
4) Jason Bay hit a three-run jack over the left field fence.
5) "Hey Amanda, you wanna share the bottle of Jack I have hidden in my drawer?"
6) The jack is the face card with the lowest value.
7) "Those bastards at the convenience store jacked me out of my change. They gave me back a 5 instead of a 10."
8) The Steelers fans were really jacked up when they realized that their team was going to the Super Bowl.
9) Ross had been hitting on Charlie's girlfriend, so Charlie challenged him to a fight and really jacked him up!
10) "You got the jack to pay for this coke?"