the other (one); the other side or counterpart (of two); used to contrast or compare two items.
このコインの一方は表、もう一方は裏です。
One side of this coin is heads; the other side is tails.
私は賛成だが、もう一方の彼は反対だ。
I'm in favor, but the other person is against it.
二つの選択肢のうち、もう一方の説明をお願いします。
Of the two options, please explain the other one.