\Di*ag"o*nal\, a. [L. diagonalis, fr. Gr. ? from to
angle; dia` through + ? an angle; perh. akin to E. knee: cf.
F. diagonal.] (Geom.)
Joining two not adjacent angles of a quadrilateral or
multilateral figure; running across from corner to corner;
crossing at an angle with one of the sides.
{Diagonal bond} (Masonry), herringbone work. See
   {Herringbone}, a.
{Diagonal built} (Shipbuilding), built by forming the outer
   skin of two layers of planking, making angles of about
   45[deg] with the keel, in opposite directions.
{Diagonal cleavage}. See under {Cleavage}.
{Diagonal molding} (Arch.), a chevron or zigzag molding.
{Diagonal rib}. (Arch.) See {Cross-springer}.
{Diagonal scale}, a scale which consists of a set of parallel
   lines, with other lines crossing them obliquely, so that
   their intersections furnish smaller subdivisions of the
   unit of measure than could be conveniently marked on a
   plain scale.
{Diagonal stratification}. (Geol.) Same as {Cross bedding},
   under {Cross}, a.

\Di*ag"o*nal\, n.
1. A right line drawn from one angle to another not adjacent,
   of a figure of four or more sides, and dividing it into
   two parts.
2. (Engin.) A member, in a framed structure, running
   obliquely across a panel.
3. A diagonal cloth; a kind of cloth having diagonal stripes,
   ridges, or welts made in the weaving.