The scientific name for the Yorkshire Terrier is Canis familiaris. This name applies to all breeds of domestic dogs.
The American Kennel Club (AKC) recognizes the Yorkshire Terrier as a single breed, regardless of size. They have breed standards, but no official distinction is made between "miniature" and "standard" Yorkies.
It's important to note that "miniature" is not a breed designation. It simply describes a smaller version of the breed.