1 [data models] The way in which features in GIS data are attached to one another functionally or spatially.
2 [ESRI software] In a geodatabase, the state of association between edges and junctions in a network system for network data models. Connectivity helps define and control flow, tracing, and pathfinding in a network.
3 [ESRI software] In a coverage, topological identification of connected arcs by recording the from-node and to-node for each arc. Arcs that share a common node are connected