雲くも形がた定じょう規ぎ

noun

French curve; irregular curve ruler

A drafting tool used to draw smooth curves of varying radii. The reading うんけいじょうぎ is less common but also valid.

• 製せい図ずの授じゅ業ぎょうで雲くも形がた定じょう規ぎを使つかって曲きょく線せんを引ひいた。

  In drafting class, I drew curves using a French curve.