Dozens of definitions of blended learning are floating around, most of them muddle-headed. Here's a collection from the excellent Handbook of Blended Learning , a collection of 39 papers edited by Curtis Bonk.
Blend of classroom and e-learning
Blend of face-to-face and e-learning
Blend of online and offline
Blend of synchronous and asynchronous
The problem with these definition is that the first two prescribe components that may not be needed in an optimal blend. The second two are too general, in that they simply divide the universe into two sets. However, the real issues with all of these definitions is that they are really definitions of blended INSTRUCTION not blended learning.
We need to look at the concept from a broader learning perspeective with definitions tat include:
Blend of formal and informal
Blend of work and learning
With these two, we move beyond blended instruction to true blended learning.