What is the difference in a rabbit burrow and a warren?

Basically a rabbit burrow is a single tunnel with, maybe, one or two side tunnels for nesting and producing babies while a warren is a complicated system of underground, connecting tunnels and side chambers which also include escape routes for the rabbit inhabitants in case of attack by predators. A burrow usually "houses" one rabbit pair plus any babies produced whereas a warren is inhabited by a large number of rabbits.