\Lat"er*al\, a. [L. lateralis, fr. latus, lateris, side:
cf. F. lat['e]ral.]
1. Of or pertaining to the sides; as, the lateral walls of a
   house; the lateral branches of a tree.
2. (Anat.) Lying at, or extending toward, the side; away from
   the mesial plane; external; -- opposed to {mesial}.
3. Directed to the side; as, a lateral view of a thing.
{Lateral cleavage} (Crystallog.), cleavage parallel to the
   lateral planes.
{Lateral equation} (Math.), an equation of the first degree.
   [Obs.]
{Lateral line} (Anat.), in fishes, a line of sensory organs
   along either side of the body, often marked by a distinct
   line of color.
{Lateral pressure} or {stress} (Mech.), a pressure or stress
   at right angles to the length, as of a beam or bridge; --
   distinguished from longitudinal pressure or stress.
{Lateral strength} (Mech.), strength which resists a tendency
   to fracture arising from lateral pressure.
{Lateral system} (Bridge Building), the system of horizontal
   braces (as between two vertical trusses) by which lateral
   stiffness is secured.