An animal's appendage refers to any part of the body that extends beyond the main structure, including limbs, tails, fins, and wings. There are several synonyms that can be used to describe these appendages, depending on the type of animal and the specific structure in question. For example, an arm or leg could be referred to as a limb, while a bird's wings are often called flight feathers or pinions. A cat's tail might be described as a caudal appendage, while a dolphin's dorsal fin is a type of dorsal appendage. Other possible synonyms for an animal's appendage could include extremity, protuberance, or outgrowth, depending on the context and the specific features being described.