A poker hand such as J♦ J♣ 4♣ 4♠ 9♠, which contains two cards of the same rank, plus two cards of another rank (that match each other but not the first pair), plus one unmatched card, is called two pair. It ranks above one pair and below three of a kind.
Between two such hands, the higher ranking pair of each is first compared, and the higher pair wins. If both have the same top pair, then the second pair of each is compared. Finally, if both hands have the same two pairs, the kicker determines the winner.
These hands are be referred to in speech, for example, as "jacks and fours" or "jacks over fours" or just "jacks on the roof" or "jacks up" (the latter is common in games where the smaller pair is rarely needed to break ties, so it doesn't need to be mentioned most of the time). Two small pairs with ranks between 2 and 9 are also sometimes referred to by the two-digit number they make: sevens and fives, for example, might be called a "seventy-five".
Examples:
- K♥ K♦ 2♣ 2♦ J♥ ("kings up") defeats J♦ J♠ 10♠ 10♣ 9♠ ("jacks up")
- 9♣ 9♦ 7♦ 7♠ 6♥ ("nines and sevens") defeats 9♥ 9♠ 5♥ 5♦ K♣ ("nines and fives" or "ninety-five")
- 4♠ 4♣ 3♠ 3♥ K♦ ("fours and threes, king kicker") defeats 4♥ 4♦ 3♦ 3♣ 10♠ ("fours and threes with a ten")
Note in particular here that the general rule about poker hands having only five cards often comes into play. If you are playing a seven-card game and have, for example, 10♣ 10♦ 8♦ 8♥ 4♣ 4♠ Q♦, the highest poker hand you can make is two pair: 10♣ 10♦ 8♦ 8♥ Q♦. The extra 4♣ 4♠ are of no consequence because you can't squeeze them into a five-card hand.