The New York strip, also called strip steak or top loin steak, is a beef steak cut from the short loin, the section of the loin that runs along the spine behind the ribs. It's valued for a balance of tenderness and rich, beefy flavor, with less marbling than a ribeye but more chew and structure than a tenderloin filet.
The cut suits dry-heat, high-temperature methods such as grilling, broiling, and pan-searing; because it's firmer than a filet, most cooks season it simply (salt and pepper) and avoid cooking it past medium to keep it from toughening. It's sold both bone-in (sometimes called a club steak, generally considered more flavorful) and boneless, and USDA grades such as Prime and Choice describe marbling and expected tenderness rather than the cut itself.
The name is popularly associated with early-20th-century New York City steakhouses, though its exact origin is disputed and not well documented. New York strip, strip steak, and top loin steak all name the same cut; the variation is regional and by-butcher, not a difference in the meat.