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.
製図の授業で雲形定規を使って曲線を引いた。
In drafting class, I drew curves using a French curve.
Standard kanji spelling for a French curve, a drafting tool.
A general template or stencil, while 雲形定規 specifically refers to a French curve for drawing smooth irregular curves.
Compound of 雲形 (cloud shape) and 定規 (ruler), describing its shape and function. The reading うんけいじょうぎ uses the on'yomi for 雲形.