A saw — a tool used for cutting wood, metal, etc. Colloquially often shortened to 'noko' (のこ).
古い机の脚を鋸で切って短くした。
I cut the leg of the old desk with a saw to shorten it.
棚を作るために、のこを借りて板を切った。
To build a shelf, I borrowed a saw and cut the boards.
金属用の鋸は刃が細かく硬い材質でできている。
Saws for metal have fine teeth and are made of hard materials.