4 Definitions

Agile is a general term and conceptual framework used to describe a number of “light-weight” methodologies, such as Extreme Programming (XP), SCRUM, and Rapid Application Development (RAD), which exhibit a series of common characteristics. Some of these characteristics include iterative analysis and development, time-boxed iterations of a predefined length, delivery of the most critical features and functions first, delivery of a complete build with an initial set of limited features within a few months (often 1-2 months), small cross-functional teams usually of 6-9 team members, daily team communication meetings, and reduced levels of documentation.
defined by Modern Analyst
Able to respond quickly to changes in the market and external political, social and physical environment.
Agile software development is a group of software development methods based on iterative and incremental development, where requirements and solutions evolve through collaboration between self-organizing, cross-functional teams. It promotes adaptive planning, evolutionary development and delivery, a time-boxed iterative approach, and encourages rapid and flexible response to change. It is a conceptual framework that promotes foreseen interactions throughout the development cycle. The Agile Manifesto introduced the term in 2001.
defined by Mariusz Kolodziej
see business agility