The term no limit in poker vocabulary describes a betting structure that has no restrictions of any kind. In a no-limit game, a player can wager any amount of chips at any point in a hand when it’s their turn to act, up to the amount they have in their stack.
The most popular game variation played as no limit is, of course, Texas Hold’em. When the action is on you in No Limit Hold’em, you can bet anywhere from one big blind to all the chips in front of you (i.e., move all in).
For example, if blinds are $100/$200 and you have $10,000 in your stack, when it’s your turn to act, you can bet $200 (which is the minimum) or any other amount ($500, $600, $2,400, etc.), up to $10,000. Despite what some movies might have you believe, you’re not allowed to add more chips to your stack mid-hand from your pocket, so the maximum you can bet is what you have in front of you when the hand starts.
This is significantly different from the other two popular betting structures, limit and pot limit. In limit games, the size of each bet is predetermined and fixed. In the pot limit, players have more freedom, but the maximum they can bet at any point is restricted by the size of the pot.
Today, no limit is by far the most popular of the three systems, primarily thanks to Texas Hold’em, which remains the most played variation in cash games and tournaments alike.