てっぺん
てっぺん · teppen · JLPT N1 · noun
top
🏔️ 天辺 = 天 (sky) + 辺 (edge, side): the top edge where you meet the sky
てっぺん is often written 天辺: 天 (heaven, sky) plus 辺 (edge, vicinity). The summit is the edge where the mountain meets the sky. The same word also means the top of your head.