[?:k]
¦ noun
1. a curve forming part of the circumference of a circle or other figure.
a curving trajectory.
[as modifier] Mathematics indicating the inverse of a trigonometrical function: arc cosine.
2. a luminous electrical discharge between two points.
¦ verb (arcs, arcing '?:k??, arced ?:kt)
1. move with a curving trajectory.
2. [as noun arcing] the forming of an electric arc.
Origin
ME: via OFr. from L. arcus 'bow, curve'.