A lattice 
is said to be oriented if 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.
