Chinese normally come up with some ways to use old terms to describe new things.

First character means “net” (can also be fishing or spider net)

Second means “line, route” (also way, sequence)

Third means, well, “hole” (but also socket)

As a combination of first and second we have “net line” - the Internet, or really any interconnected net like a power grid. Third doesn’t need an explanation, I think.