A connection is a single connection between two things. Connectivity describes the state of (possibly) multiple connections. So - you need at least one connection, to get connectivity. Multiple connections might improve the connectivity. Say you had two towns, with three data connections between them. If your system was connected in such a way that data could be routed through any of the connections, and at least one of the connections was OK, you would have connectivity between the towns. If all of the connections were broken you would have no connectivity between the towns. If only one of the connections was working, you might have limited connectivity, perhaps because there was not enough speed. If two of the connections were connected, you might have full connectivity, as long as people did not try to do too much downloading!

Very simply put: CONNECTION is the act of connecting CONNECTIVITY is the state of being connected. Examples of use for connectivity: The benefits of global connectivity. This laptop has limited connectivity. Hope this helps.