• 兄あに — older brother
• 兄弟きょうだい — siblings / brothers
• 実兄じっけい — biological older brother
• 兄貴あにき — respected older brother
• 義兄ぎけい — brother-in-law (older)
• 兄上あにうえ — honored older brother

兄 combines a component suggesting the head with 儿, the “legs” radical, forming the image of a person standing above others.

This came to represent an older brother or senior figure, and the kanji often carries a sense of responsibility or leadership.