I found this term interesting. Searching through the web and wiki results in the following meaning: Seclusion, Isolation, often valued as a time when one may work, think or rest without being disturbed.
The headline of the latest BusinessWeek is about overworked Americans, but I think it is not only valid for American, but also to most of us here. The key message from those articles is that, we sometimes spend most of our time in a meeting, discussion, or other type of collaboration, which in some circumstances, not really necessary. But we do it anyway.
So, they come out with the word: solitude. Sometimes, we might just as well rethink the necessity to be involved in such collaboration. We might sometime needs to question the request for someone to join a meeting, conference call, or any other thing. We need to seclude ourselves, secluding from the others to focus on our creativity and innovation, or maybe just spend the time for ourselves and family.