Can you go alone in euchre if your partner orders?

During a loner or lone hand, the bidder's partner discards their cards, and does not participate in play of the hand. In some regional variants (see below), if the dealer's partner "calls them up"/"orders it up" (on the turned up card), they are obliged to go alone for that hand.

What is the Jack of Diamonds rule in the game of hearts?

The Jack of Diamonds is used as in the variations above. Whoever captures the Ten of Clubs doubles their score for that hand. After the pass but before the first lead each player may "turbo-charge" one of the following cards: Ace of Hearts, Queen of Spades, Jack of Diamonds, or Ten of Clubs.

Why is the Jack the highest card in Euchre?

In the game, the Bower (the Jack) is the most powerful card, overturning the King and Queen. Euchre scholars believe "bower" is an Americanized form of the German word for peasant, or farmer: "bauer." In euchre, the farmer (i.e. the common person), is the most powerful player in the game.