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.
