"I take the point about what the majority use becoming the norm, but legs and tails do have functional differences, and these would require some differentiation in any useful language. So a "tail" would never become a "leg", not being capable of operating as one. Whatever you called the total set of extremities."

True, but if the definition of "leg" is only "thin extremity" (I say "thin" to exclude the head), then a dog would have four running legs and one wagging one. Of course, if "head" means "an extremity not used for locomotion," then it comes close to creating a two-headed dog (the wagging head and the barking head).

This would then result in having to decide between two-headed four-legged dog and a a one-headed, five-legged dog.

It all comes down to function-based definitions vs. similarity-based ones. You could even make your definitions so specific that there could be a different term for front legs and back ones, eliminating the need for the adjectives "front" and "back," I suppose.

It's fun to play with this stuff, isn't it?


Bob