What does miniature mean?
Miniature means very, very small, but generally in comparison to the 'natural' or 'common' size. It does not have a specific size connotation.
For example, you have horses and miniature horses, as well as poodles (standard poodles) and miniature poodles. The miniature version of each is much smaller than the regular version, but the miniature horses and the standard poodles are comparable in size.