The river poker term refers to the last card given in all poker variations. In versions like Hold’em and Omaha, which use community cards, the river card is also known as fifth street. In stud poker games, the river card is known as seventh street.
The action of hitting the right card on the river is said to be “rivering” the card, and the player who often makes their hand on the river is amusingly called a river rat.
For example, if you have four of the five cards needed for a flush or straight after the turn and the river helps you make your hand, you can say that you’ve “rivered” that card.