Final answer:
The excess fat that is trimmed from the carcass for cuts is called subcutaneous fat. It is situated beneath the skin and differs from intramuscular fat, which is within the muscle, and intermuscular fat, which is between muscles.
Step-by-step explanation:
The term for fat that is in excess and must be trimmed from the carcass for cuts is subcutaneous fat. This type of fat lies beneath the skin and over the muscles, and it's also the layer of fat that is most commonly associated with the marbling of meat. It is different from intramuscular fat, which is found within the muscle itself and contributes to the flavor and juiciness of the meat. External fat is another term that is sometimes used interchangeably with subcutaneous fat, but it is less specific. Intermuscular fat, on the other hand, is found between the muscles and is also known as seam fat.