The truck jack-knifed on the icy road.

He had a collection of jack-knives.

He jack-knifes off the diving board.

He is jack-knifing off the diving board.

The jack of spades is the highest-ranking card in the deck.

Jack of diamonds is a playing card in a standard deck of cards.

Jack of clubs is a playing card in a standard deck of cards.

Jack Pudding is a funny character in the play.

I tried jack-fruit for the first time and it was delicious.

I carved a spooky jack-a-lantern for Halloween.