Definition of arc

• n. - A portion of a curved line; as, the arc of a circle or of an ellipse.
• n. - A curvature in the shape of a circular arc or an arch; as, the colored arc (the rainbow); the arc of Hadley's quadrant.
• n. - An arch.
• 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.
• n. - A portion of a curved line; as, the arc of a circle or of an ellipse.
• n. - A curvature in the shape of a circular arc or an arch; as, the colored arc (the rainbow); the arc of Hadley's quadrant.
• n. - An arch.
• 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.