a senior (at school or work); someone with earlier entry or more experience; an elder or superior in a group.
田中さんは私の先輩で、仕事をよく教えてくれます。
Mr. Tanaka is my senior and often teaches me work-related things.
先輩に相談したら、的確なアドバイスをもらえた。
When I consulted my senior, I received accurate advice.
文化祭では先輩が中心になって準備を進めた。
At the school festival, the seniors took the lead in preparing.
職場では先輩後輩の関係が大事にされることが多い。
Workplaces often place importance on senior-junior relationships.