Chop
Also called split pot
A chop (also called a split pot) is when two or more players make the exact same best five-card hand and divide the pot evenly between them.
A chop happens when the showdown produces a tie: two or more remaining players end up with five-card hands of identical rank, so no single winner can be declared. The pot is split as evenly as possible among the tied players, and any odd leftover chip typically goes to the first player to the dealer's left.
It comes up most often when the five community cards on the board already make the best possible hand and everyone's hole cards add nothing, or when two players hold the same pair with the same supporting kickers. You'll also hear "chop it" used casually when the action folds around to the two blinds and they agree to take their blinds back rather than play it out (a "blind chop") instead of playing the tiny pot heads-up.
For a beginner, the key takeaway is that ties are decided by the best five cards each player can form, and a higher side card (the kicker) is often what saves you from a chop or costs you the whole pot. Knowing when your hand can only ever tie helps you avoid overbetting a spot where the most you can win is half.
Example
You hold A-Q and your opponent holds A-J; the board comes A-K-Q-J-10, so you both simply play the board for a Broadway straight (A-K-Q-J-10) and the pot is chopped 50/50. If the board were instead A-K-7-4-2, you'd win outright: both of you have a pair of aces with a king kicker, but your queen kicker beats their jack.