oniisan

Oniisan is a Japanese term that translates to "older brother." It is a polite and affectionate way to refer to one's own elder brother or the elder brother of someone else. The term can also be used more broadly to address any young man who is slightly older than the speaker, especially in informal situations where a sense of familial warmth or respect is intended. The usage is similar to how "brother" might be used in English to address a close male friend or acquaintance, though "oniisan" carries a more specific connotation of seniority.

While primarily used for biological older brothers, its application extends to older male cousins, close family friends, or even characters in manga and anime who are depicted as older brothers. The suffix "-san" is a common honorific in Japanese, indicating politeness and respect. Therefore, "oniisan" is a polite form, distinct from the more casual "aniki" which can sometimes imply a leadership role or a tougher, more street-oriented relationship. The term reflects the importance of familial bonds and hierarchical respect in Japanese culture.