The crossword solution for the term 'BIG CUT OF TUNA' is 'STEAK'. A STEAK is a cut of meat, usually beef, that is cut across the muscle fibers. It is usually grilled or pan-fried and served with various accompaniments. Steaks are often served as a main course in restaurants and can be found in many grocery stores. Tuna, on the other hand, is a type of fish that is typically served raw or cooked. It is a popular ingredient in sushi and is also used in salads, sandwiches, and other dishes.