The American Board of Medical Specialties (ABMS for short) is like a special club that makes sure doctors know what they're doing and are really good at it.
It's sort of like if you want to be in the dinosaur club, you have to know a lot about dinosaurs and be really good at finding their bones before they let you join.
The ABMS club works the same way, but for doctors. They test doctors to make sure they know all about the body and how to take care of people when they're sick. If the doctor passes the tests, they get special certificates saying they're really good at taking care of people.
Just like dinosaurs have different types, like T-Rex or Stegosaurus, the ABMS has different types of doctors they test. They have doctors who know a lot about the heart (cardiology), the bones (orthopedics), and even the brain (neurology).
So when you go to see a doctor, you can feel better knowing they're in the ABMS club and have proven they know how to take care of you!