What does 同士 mean?
同士 is a Japanese noun meaning “one another, companion, comrade” in English. It is written as 同士 in kanji, どうし in hiragana, and doushi in romaji. This word is part of JLPT N3 vocabulary.
Example sentence
１０代の友だち同士が徹夜でおしゃべりした。
The teenage friends stayed up talking all night.