Which term does not fit with the others regarding a raptor's anatomy?

The term "train" does not align with the other anatomical terms when discussing a raptor's anatomy. In the context of raptors, anatomy typically refers to parts that are integral to their physical structure and function, particularly those related to hunting and perching.

Talon refers to the sharp claws that raptors use to grasp and kill their prey. The tarsus is the part of the leg that connects the foot to the body, which provides support and aids in perching and hunting. The hallux is a specific toe that allows raptors to have a strong grip on their prey and helps in perching.

"Train," on the other hand, refers to a structure in the tail feathers of some birds, particularly in domestic species bred for ornamental purposes, but it does not have a significant role in the anatomy relevant to hunting or the physical abilities of raptors. Therefore, it is the term that stands apart from the others in this context.