Out is a poker term for a card that can help improve a player's combination to potentially give him a winning hand.
For example, if you have an open ended straight draw like 98 on 762, you can improve to a straight by hitting any tenor any five, meaning you have 8 outs to hit a straight. On top of that, you have three outs to hit a nice and three outs to hit an eight, which would give you a top pair, and that might also be a winning combination some of the time.
It is essential to understand how many outs you have with different draws since then you can make a math-based decision and know if you are getting the right odds for the call.
When you know the number of outs you have to improve your hand, you can multiply it by 2 to see what are your odds of hitting your hand on the next card or by 4 if you have two cards to go.Continuing our previous example, let’s assume you will always win when you hita straight and have 8 outs for that. In this case, your odds would be around16% to get that card on the turn and around 32% to hit it by the river. Of course, these numbers are not exactly precise, but they are very close to it and significantly simplify the calculation process.
When you know your chance of hitting the cards you need, you can compare it to pot odds and make the right decision rather than relying on your feelings or making emotional judgments.