Simple Definition: A generic type of dinosaur that ate meat.
Complicated Definition: Any of a type of Dromaeosaur (a subgroup of theropods) that lived a long time ago and is now believed by most to be extinct, though there are still some potheads (no offense) out there that think dinosaurs are still alive. Raptors had many distinctive features, the most memmorable was a huge claw on each foot used for disemboweling other dinosaurs. The shape of this claw is referred to as 'sickle shaped' so often that it is annoying.
I'm not an expert on the topic, I just did a little research before I posted, therefore, the information herein is not guaranteed to be 100% accurate.
Utahraptors, velociraptors, and Deinonychuses are all raptors.