Tri-tip steak is cut from a tri-tip roast, which is a small, triangular cut from the sirloin. The tri-tip was popularized in California but is now more widely marketed, although you may need to request it from your butcher. It is also known as a triangle steak or bottom sirloin steak. Each steak is boneless, about 3/4 to 1 inch thick, and should be nicely marbled. You'll be pleased with the rich beef flavor and tender texture, as well as the cheaper price tag than similar steak cuts.