一方 (ippō) means “one of two” | MotiTan Japanese Dictionary

More examples

二つの道のうち、一方を選びます。futa tsu no michi no u chi ip pō o era bi ma su

I choose one of the two roads.

It selects one side or member from two possible sides or members.

片方katahō: One member of a pair, often referring to a physical item or one side.

二つあるもののうち、どちらか一つ。futa tsu a ru mo no no u chi do chi ra ka hito tsu

The word comes from the Sino-Japanese elements 一 (ichi, "one") and 方 (hō, "direction or side"); 一方 (ippō) means one side of a pair.

When the two items are already clear from the conversation, 一方 (ippō) lets speakers refer to one of them without repeating its name.