1Two or more things being exactly the same — identical to the point of being indistinguishable.
指紋を照合した結果、犯人と同一人物であることが判明した。
A fingerprint comparison revealed that he was the same person as the culprit.
二つの契約書の内容が同一かどうか、一行ずつ確認した。
I checked line by line whether the two contracts were identical in content.
このロゴは以前の会社のものと同一だと訴えられた。
They were accused of using a logo identical to that of the previous company.
2Treating everyone the same way, without discrimination based on who they are.
どの国籍の応募者にも同一の基準で審査を行う。
Applicants of every nationality are screened using the same criteria.
同一労働同一賃金の原則が、この会社にも導入された。
The principle of equal pay for equal work has been introduced at this company too.
教師は生徒全員に同一の態度で接するよう心がけている。
The teacher tries to treat all students with the same attitude, without favoritism.