Edge connectivity refers to the minimum number of edges that need to be removed from a graph to disconnect it. In simpler terms, it measures how well-connected the vertices of a graph are. A higher edge connectivity indicates a more robust structure, as it requires the removal of more edges to separate the graph into distinct parts. In graph theory, edge connectivity is denoted as λ(G), where G represents the graph. It plays a crucial role in network design and reliability, helping to assess the vulnerability of networks like computer networks or transportation systems to failures or attacks.