n. & v.
--n.
1. part of the circumference of a circle or any other curve.
2 Electr. a luminous discharge between two electrodes.
--v.intr. (arced; arcing) form an arc.
Phrases and idioms:
arc lamp (or light) a light source using an electric arc. arc welding a method of using an electric arc to melt metals to be welded.
Etymology: ME f. OF f. L arcus bow, curve