Definition of cash out
The action of "cash out" is the act of withdrawing money from a room of poker. You can "cash out" in part or in whole. For example, we deposit 100 euros on a room of poker, we play several months and we raise our balance to 500 euros. You might want to "cash out" 100 euros, our initial deposit, to tell yourself that you are playing with your winnings only. Some rooms require a minimum of cash out and we will have a maximum of cash out possible per day (and week). Each room has its own rules of cash out. Generally, the money will be deposited by the deposit method. So, if you had deposited 100 euros on the gaming room with your credit card, your cash out will be returned to your credit card. This is mainly to avoid fraud.
Cash out partly to the money
If you play poker in some casinos, you may have to buy chips to play the money games. These chips will be valid in the casino only. So, for example, you buy $200 worth of chips and you sit down at a table with your $200 stack. If at the end of the evening you leave, you will have to go "cash out" your chips to exchange them for money.