All-in is a term most frequently used by poker players when wagering all of their remaining chips into the pot.
Technically, all-in is similar to raising, except that instead of raising a specific amount, you are raising everything you have left. In order for someone to call your all-in, they need to have more chips than you do. Otherwise, they will be going all-in as well.
For example, let’s say that you have $150,000 chips and you announce that you are all-in. If only one player who has $70,000 calls, this means that you are technically betting only $70,000 into the pot while the rest is given back to you.
However, if you’re all-in with $150,000, and someone with $300,000 calls, that means they are only contributing additional $150,000 to the pot instead of all $300,000.
After a player announces that they are all-in, they can’t take any more action until the round ends.