Senpai is a word in Japanese language that means someone who is older than you or has more experience than you in a particular field or school. Think of it like someone who is in a higher class or grade than you in school. They might be more skilled and knowledgeable than you in certain areas, like a sport or a subject. When you call someone "senpai", it shows respect for their experience and position. It's like saying "Mr." or "Ms." to a teacher. Sometimes in anime and manga, the term "senpai" might be used as a romantic interest by a younger character towards an older character they admire and respect.