Primarily a geometric term for a part of a circle's circumference. Also used in technical fields like engineering and design.
Draw an arc with a compass.
This bridge forms a beautiful arc.
I drew an arc using a compass.
The road curves along an arc.
This design uses a 90-degree arc.
円周 refers to the entire circumference of a circle, whereas 円弧 refers to only a portion (arc) of that circumference.
Compound of 円 (circle) and 弧 (arc). The kanji 弧 itself carries the meaning of a curved shape or bow.