pen nib
Refers to the metal writing point of a fountain pen, dip pen, or similar instrument.
万年筆のペン先が曲がってしまった。
The nib of my fountain pen got bent.
This pen's nib is fine, so I can write neatly with it.
I traced lightly over the paper with the tip of the nib.
Compound of ペン (pen, from English) and 先 (tip, point).