Yes, as the others have said, there is no "real
teacup", it is just a term that people use (namely breeders) as a
sales pitch to advertise really tiny pups

But yeah, ok, alot (not all) breeders do "consider" pups that grow to be 4 lbs or under a "teacup". However, I wouldn't use this term if I were you...it upsets alot of people! LOL