any part of a curved line.-usually a curved member made up of separate wedge-shaped solids, with the joints between them disposed in the direction of the radii of the curve; used to support the wall or other weight above an opening. in this sense arches are segmental, round (i. e., semicircular), or pointed.-a flat arch is a member constructed of stones cut into wedges or other shapes so as to support each other without rising in a curve.-any place covered by an arch; an archway; as, to pass into the arch of a bridge.-any curvature in the form of an arch; as, the arch of the aorta.-to cover with an arch or arches.-to form or bend into the shape of an arch.-to form into an arch; to curve.-chief; eminent; greatest; principal.-cunning or sly; sportively mischievous; roguish; as, an arch look, word, lad.-a chief.