ZZ Method Tutorial Part 2: Edge Orientation Detection
Part 3: • ZZ Method Tutorial Part 3: Orienting Edges
Definition excerpts are from Conrad Rider's tutorial: http://cube.crider.co.uk/
Formal definition: "An edge is defined as oriented if it can be solved using only R, L, U and D face turns. If an edge cannot be solved using these face turns then it is a misoriented or 'bad' edge."