Syllogism

The Technical Stuff:
A Syllogism is a form of reasoning in which two propositions or premises are stated and a logical conclusion is drawn from them. Each premise has the subject-predicate form, and each shares a common element called the middle term.

Example: 

• Dr. House: Words have set meanings for a reason. If you see an animal like Bill and you try to play fetch, Bill's going to eat you, because Bill's a bear.
  Little Girl: Bill has fur, four legs, and a collar. He's a dog.
  Dr. House: You see, that's what's called a faulty syllogism; just because you call Bill a dog doesn't mean that he is . . . a dog.
  ("Merry Little Christmas, House, M.D.)