A pair of lovers; two people who are in a romantic relationship (girlfriend and boyfriend, or a couple).
公園で恋人同士が手をつないで歩いていた。
A couple of lovers were walking hand in hand in the park.
映画は恋人同士のすれ違いを描いたラブストーリーだ。
The movie is a love story depicting the misunderstandings between a couple.
恋人同士で旅行に行く予定です。
We're planning to travel as a couple.
彼と彼女は恋人同士だと周囲に知られている。
Everyone knows that he and she are a couple.