Definition of IL

I find myself tempted to create my own hybrid defintion of IL since I can't seem to find one that exactly matches what I was thinking. At the beginning of this subject I probably would have latched onto the ALA definition without hesitation, and while I still find it the best that is out there, I feel it neglects to mention the importance of IL in enabling someone to be a lifelong learner. However, should this be something that is not included in a definition of IL but rather as a justification for the importance of an IL program.