同伴 (tóng bàn): 동반자.

At summer camp, I met a companion from Shanghai. We climbed mountains and played games together every day and soon became good friends.

While hiking, the guide reminded us not to act alone and to keep in touch with our companions so we wouldn't get lost in the forest.

When she first went abroad to study, she was very lonely. Later she found several companions in her language class. They often cooked and went shopping together on weekends, and life became much more interesting.

In the research project, my companion and I divided the work: he collected data and I analyzed the results. In the end, we finished the report on time.