Show
To show is to expose your cards. At showdown, you show your hand to determine the winner.
The simple explanation
When the betting is over, the remaining players turn their cards face up. You may also show cards by choice, for example after a fold, but not while the hand is live.
A closer look
Rules differ on whether a player must show. Usually the last aggressor shows first, and a winning hand must be shown to win the pot. A player who folds has no obligation to show, and showing a folded hand can give information. In some rooms, showing cards to one player gives others the right to see them.
A practical example
Full explanation
To show is to expose your cards. At showdown, you show your hand to determine the winner.
To show is to expose your cards.
It happens at showdown.
The last aggressor shows first.
Showing folded cards gives information.