Arc

[Fr. from Lat. arcus, a bow, an arch. Etymol. uncertain.] ( Geom.) A portion of a circle or other curved line. The arc of a circle is the measure of the angle formed by two straight lines drawn from its extremities to the centre of the circle. The straight line joining the ends of an arc is its chord, which is always le than the arc itself. In Fig.177, dd is the chord of the arc dhd. -An arch; a vault. Arc, Joan of. See JOAN OF ARC. Ar'ca, n. [Lat.] ( Antiq.) A chest, in which the Romans were accustomed to place their money; the coffin in which persons were buried, or the bier on which the corpse was placed previously to burial. ( Zool .) A gen. of bivalve shells, distinguished by their great number of teeth, resembling those of a fine saw. Arcada, or Arcade, in Michigan , a township of Gratiot co. -A township of Lapeer co.