NeighborhoodGraph
NeighborhoodGraph[g, v] gives the graph neighborhood of a vertex v in the graph g.
NeighborhoodGraph[g, v, d] gives the neighborhood up to distance d.
Examples
Neighborhood of a vertex:
NeighborhoodGraph[GridGraph[{5, 5}], 13]Up to distance 2:
NeighborhoodGraph[GridGraph[{5, 5}], 13, 2]Please visit the official Wolfram Language Reference for more details.