Origin of the word river in poker?

Answer 1

The river card is the last community card to be dealt. It proceeds the final round of betting and is responsible for administering more than its fair share of bad beats. A player might say that he "hit an Ace on the river," meaning that he paired an Ace from his hand with the river card.

In the 1800's Poker games were regularly held aboard riverboats, where cheating players were known to deal an extra community card in order to give themselves an advantage. Such miscreants were often tossed overboard into the water, and hence the final community card become known as 'the river card'.