Suit is casino jargon that refers to different types of playing cards. There are four different suits in a standard 52-card playing deck, and they are clubs, spades, hearts, and diamonds. In standard decks, every suit has one of each denomination, including face cards. In other words, one suit has all cards from deuce to ace.
If you have played poker before, chances are that you have heard another player say they had, let’s say, ace-king suited. What they meant by that is that they had an ace of spades and a king of spades or perhaps an ace and a king of hearts or any other same suit.