The Generally Accepted Accounting Principles exist to ensure that American accountants are using the same or almost the same standards so that comparison of financial statements between or within a company is easy and accurate. They also promote transparency in accounting. The GAAP are set by the FASB.
According to the FoodTV Encyclopedia for Delmonico Steak, the Delmonico steak is a boneless top loin steak, which is also called a New York strip steak and a Kansas City strip steak. (With the bone in, it is usually called a club steak.)
I recently bought a pkg of ribeye steaks at the supermarket that were called Delmonico.. They were really inexpensive ($9 for four, each about 4 x 2 and 3/4 thick). I cooked one tonight and it was really good.