T-Bone steaks, Club steaks, and
Porterhouse steaks are the same. T-Bone Steak must be at least
0.25" thick. Any smaller, it would be called a Club Steak. The
filet portion of a Porterhouse must be at least 1.25" thick at
its widest point.
A center T-shaped bone divides two sides of the steak. On one
side is a tenderloin Filet and the other is a top loin, better
known as the New York Strip Steak. If you cut the bone out,
you get a Filet and a New York Strip. If you leave one side on
the bone, you get either a bone-in Filet or a bone-in New York
Strip.
So, all T-bones contain a filet and a New York Strip and all
Porterhouses are T-bones, but not all T-bones are
Porterhouses.
Incidentally,
Ribeye and Rib Steak are the same. The Ribeye is boneless
and the Rib Steak includes the rib bone, and is often called
a Bone-In Rib Eye Steak. In Australia, when the bone is
removed, it is often called a "Scotch Filet". Other names
include: Beauty Steak, Market Steak, Delmonico Steak, and
Spencer Steak.