Trips is a poker slang term for a three-of-a-kind hand made from one hole card and two community cards.
You can only make trips with an unpaired starting hand. This makes trips different from a set, as the latter is a three-of-a-kind made when you hold a pocket pair and hit the same card on the community cards.
Trips are a bit less valuable than sets since they are not that disguised, and two players can have trips at the same time when only one can have a particular set in any given hand.
For example, let’s say you raise from the BTN with Q9s, and the flop comes AQQ, bringing you a three-of-a-kind combination known as the trips. If you move all in on the flop, another player can also have trips, and it will depend on the runout and kicker who wins it. In these situations, you can even consider running it twice to reduce the variance.