At the showdown all remaining player's hands are compared to determine who has the highest-ranking hand. Listed below are the universally accepted Poker hand rankings (from highest to lowest).

ROYAL FLUSH
The highest possible ranked hand. To achieve this hand you need an Ace, King, Queen, Jack, and 10 of the same suit.
(Example: A , K , Q , J , 10 )

STRAIGHT FLUSH
Five cards of the same suit in ascending order.
(Example: 8, 7, 6, 5, 4 )

FOUR OF A KIND
Four cards of the same value.
(Example: K, K, K, K )

FULL HOUSE
Three of a kind and a pair. The player with the higher value three of a kind, wins in the event of a tie.
(Example: A, A, A, 5, 5 )

FLUSH
A hand containing five cards of the same suit. If two players have the same hand the winner is the player holding the highest valued cards.
(Example: Q, 10, 6, 3, 2 )


STRAIGHT
Five cards of any suit in ascending order. The ace can be either high or low and the high straight wins the tie.
(Example: 10, 9, 8, 7, 6 )

THREE OF A KIND
Three of a kind is simply three cards of the same value.
(Example: 8, 8, 8 )

TWO PAIR
Two sets of pairs.
(Example: 3, 3, Q, Q )

The player holding the highest pair takes the pot in the event that more than one player is holding two pairs.

PAIR
One pair of cards in a hand.
(Example: J, J or 5 , 5 )

HIGH CARD
Highest card takes all in the event there is a complete absence of the above hands.