An oriented lattice is a lattice 
for which there exists a rule which assigns a specified direction
to any edge connecting arbitrary lattice points 
. In that way, an oriented
lattice is intimately connected to an oriented graph.
Given a point lattice 
,
one common such rule is the so-called north-east rule which orients each edge of
in the direction of increasing coordinate-value.
This type of ordered lattice is central in a number of fields, e.g.,in oriented
percolation models within the field of discrete
percolation theory.
