A “Monkey” in Blackjack is any card valued at 10, and typically refers to a Ten, Jack, Queen, or King. In games where players may be dealt two cards, a Monkey is a very desirable starting hand. If an Ace is counted as 11, then two Monkeys make a hand worth 21 points, ensuring a win for the dealer.
For this reason, most Blackjack players prefer to be dealt two Monkeys rather two Aces, as the Blackjack is guaranteed with the Monkeys.