The term 'Nocturnal Arboreal Marsupial' refers to a type of animal that is active at night, lives in trees, and has a pouch for carrying its young. The most common example of this type of animal is the possum, which has six letters. Possums are found in many parts of the world, including Australia, New Zealand, and North America. They are omnivorous, meaning they eat both plants and animals, and they are nocturnal, meaning they are active at night. Possums are also arboreal, meaning they live in trees, and marsupial, meaning they have a pouch for carrying their young.