伯はっ兄けいMeanings1nouneldest brother; eldest sonArchaic or literary term for one's eldest brother. In modern Japanese, 長男 (ちょうなん) or 一番上の兄 (いちばんうえのあに) is more common.古こ文ぶん書しょには「伯はっ兄けい」と記しるされているが、現げん代だいではほとんど使つかわれない。In old documents it is written as 伯兄, but it is hardly used today.