8:1 Incidental Vocabulary Learning

Where and when did I find this word?
I found this word in the book, Word Wise and Content Rich, by  Fisher and Fry.  It is in a chapter that focuses on making vocabulary instruction a school wide initiative.  The word was found in the following context:
     "Wide reading is of educational interest in part because of the connection to incidental vocabulary
     learning."
Wide reading is a sort of encompassing term for a variety of reading programs that aim to instill reading habits in students.

What does this word mean?
According to Fisher and Fry, incidental vocabulary learning occurs as an unplanned (although not necessarily unintentional) event.

Do I want to know this word and why?
As a teacher, I do want to know this word.  According to the authors of the book, incidental learning is a vital part of the learning design of simulations because marshaling complex tasks can't be effectively taught in a strictly linear fashion.

Do I want others to know this word?
Teachers should absolutely know this word.  This concept of incidental learning is closely related to the Matthew Effect.  Stanovich (1986) coined this term after reading a passage in the Bible about the rich getting richer (Fisher and Fry).  It is important that teacher understand that learners that read more get better at reading because of the incidental learning that occurs, and therefore they read ever more (Fisher and Fry).  It's also important for teachers to understand that motivation and interest play leading roles in such concepts as incidental vocabulary learning and the Matthew Effect.