What does 同一 mean?
同一 is a Japanese noun meaning “identity, sameness, similarity” in English. It can also be translated as “fair” depending on context. It is written as 同一 in kanji, どういつ in hiragana, and douitsu in romaji. This word is part of JLPT N3 vocabulary.
Example sentence
これは私が先日なくしたのと同一の鉛筆である。
This is the same pencil that I lost the other day.