Legal definition? I don't know if they actually do what you are looking for here. There's a statute for forcible rape and one or more for non forcible. They are left vague so they they cover many situations, and the prosecution has the opportunity to decide which fit best.

Some people don't believe that certain situations are "real rape". I have heard arguments that if the victim was unconscious then it wasn't "rape rape" because she didn't know it was happening. Same for those in a medical facility raped by a caregiver while they were sedated. It's horrifying to hear this argument. Some people think that consent can't be revoked, that going outside agreed parameters (like wearing a condom) isn't a violation of consent, etc.