If you were to look at a cow and a deer comparatively, & try to find a common terminology between them, here goes:
On beef, you would call the inner tenderloins "Fillet Mignon", and the outer backstraps would be called a "Ribeye" or a "New York Strip", depending on location from the back of the neck to the hindquarters.
If you order a beef "porterhouse "steak, which BTW is my favorite, you will have a New York Strip on one side of the backbone & part of the rib, and a smaller fillet mignon on the other side. A T-bone steak is very similiar to a porterhouse, but usually lacks the Fillet Mignon, which can be marketed at a much hugher price per lb.
I worked as a butcher commercially for 6 years, now just process may harvested each year for myself. Vernacular can vary I'm sure, but this is the best explanation i can give.
