In my research, I defined agility as:
"...a software development team’s ability to create change, respond to change and learn from change so that it can better deliver value."
Someone commented to me that the "create change" part of this definition was unusual: what does it mean?
Agile software development actively encourages the customer to change the requirements of the product being built – to maximise the value they get from the product – with the development team "embracing" this change. As the customer sees (and hopefully uses) the evolving product, they become confident that they can refine and add new (high priority) requirements that maximise the value they get from the product, rather than pulling new requirements from a bucket of preconceived ideas. Agile development gives the customer confidence that changes can be made successfully and easily. In contrast, traditional development methods discourage change by making change difficult.
While not specifically talking about agile software development, the author Donald Gerwin defined creating change as: "...driving new change that would never have occurred were it not for the entity’s actions, e.g., creating more uncertainties for rivals, thus establishing a powerful competitive advantage." (*)
While responding to change is the crucual part of the definition of agility, creating change and learning from change are also important.
(*) Manufacturing Flexibility: A Strategic Perspective, Donald Gerwin, 1993. (Sorry, not available for free.)