1. senior (at work or school); superior; elder; older graduate; progenitor; old-timerSee also 後輩 こうはい
Wikipedia definition
2. Senpai and kōhaiSenpai and kōhai and kōhai are an essential element of Japanese seniority-based status relationships, similar to the way that family and other relationships are decided based on age, with even twins being divided into elder and younger sibling. Senpai is roughly equivalent to the Western concept of mentor, while kōhai is roughly equivalent to protégé, though they do not imply as strong a relationship as these words mean in the West.
Read “Senpai and kōhai” on English Wikipedia
Read “先輩” on Japanese Wikipedia
Read “Senpai and kōhai” on DBpedia


to talk about this word.