In a new curriculum developed in Iowa called "Connections Matter" (go to www.connectionsmatter.org to learn more about this community-based initiative), trainers are using a working definition that is user-friendly:
Resilience= the ability to thrive, adapt and cope despite hard times
As part of this working definition, it is noted that resilience doesn't happen in a vacuum and I was thinking about this as I read the posting on character. The more we learn about resilience (howvever we define it!), the more we recognize that resilience happens within context--systems such as family, school, neighborhoods and communities. This is the latest generation of resilience research and it is what is driving our work to look at family and community resilience to understand more about how these systems influence individual resilience.
Regarding the brain, yes, as you noted plasticity of the brain is a core ingredient of our resilience and capacity to heal. There's an intriguing article called "The Resilient Brain" by Sandra Upson in the July/August, 2013 issue of Scientific American Mind that you might find interesting. To me, neuroplasticity is the essence of why it is never too late to heal and thrive.