[AnimalMuppet]

True, and if you're thinking of them as a pair, then "first" and "second" are appropriate. But if you're using them to implement a list, then "second" is misleading.

[frou_dh]

I'd probably go with "left" and "right" to get away from the implication of priority. I didn't type this using my first and second hands.

(bikeshedding acknowledged)