If you’re searching online or asking around about dinosaur party ideas, you might see the term Three-Rex come up a lot. This isn’t a secret code or some weird trend; it’s basically a dinosaur party for a three-year-old. So if your kid is about to turn three, this theme could work for you. It’s just a play on words, similar to Two-rannosaurus and DinoFOURus. T-Rex typically takes center stage at a Three-Rex party, but it doesn’t need to be the only dino in on the action.