Wiktionary
navigation mesh
n. (context computing English) A data structure used in artificial intelligence applications to aid agents in pathfinding through large spaces.
Wikipedia
Navigation mesh
A navigation mesh, or navmesh, is an abstract data structure used in artificial intelligence applications to aid agents in pathfinding through complicated spaces. This approach has been known since at least the mid-1980s in robotics, where it has been called a meadow map, and was popularized in video game AI in 2000.