A star chart showing various ley lines
A ley line is a straight line connecting two places. These lines were believed to have special powers and/or were based on paths laid down in the past. The aggregation of ley lines creates a network.
In the Milky Way Galaxy, there was one such network in the Alpha and Beta Quadrants. The Federation was aware of its existence in the early 2260s.
Interdimensional space folds along ley lines. (SNW: "New Life and New Civilizations")