arc

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Something shaped like a curve or arch: the vivid arc of a rainbow.
2. n. Mathematics A segment of a circle.
3. n. An electric arc.
4. n. Astronomy The apparent path of a celestial body as it rises above and falls below the horizon.
5. v. To form an arc.
6. v. To move or seem to move in a curved path: the stars that arc across the sky.

Century Dictionary and Cyclopedia

1. n. In geometry, any part of a curved line, as of a circle, especially one which does not include a point of inflection or cusp. It is by means of arcs of a circle that all angles are measured, the arc being described from the angular point as a center. In the higher mathematics the word arc is used to denote any angular quantity, even when greater than a whole circle: as, an arc of 750°. See angle.
2. n. In astronomy, a part of a circle traversed by the sun or other heavenly body; especially, the part passed over by a star between its rising and setting.
3. n. In architecture, an arch.
4. n. Obsolete form of ark.
5. n. An abbreviation of Associate of the Royal College of Organists.

Wiktionary

1. n. graph theory A directed edge.
2. v. intransitive To move following a curved path.
3. v. intransitive To form an electrical arc.

GNU Webster's 1913

1. n. (Geom.) A portion of a curved line.
2. n. A curvature in the shape of a circular arc or an arch
3. n. obsolete An arch.
4. n. The apparent arc described, above or below the horizon, by the sun or other celestial body. The diurnal arc is described during the daytime, the nocturnal arc during the night.
5. v. (Elec.) To form a voltaic arc, as an electrical current in a broken or disconnected circuit.

WordNet 3.0

1. n. something curved in shape
2. v. form an arch or curve
3. n. a continuous portion of a circle
4. n. electrical conduction through a gas in an applied electric field