noun
awl; eyeleteer
A pointed tool used for piercing holes in materials such as leather, paper, or cloth; also used for making eyelets.
革に穴を開けるために千枚通しを使った。
I used an awl to make a hole in the leather.
Compound of 千枚 (senmai, 'a thousand sheets') and 通し (tōshi, 'piercing'), referring to a tool that can pierce through many sheets.