Validation

The process of: (a) evaluating a system or component during, or at the end of the development process to determine whether it satisfies specified requirements; or, (b) providing evidence that the software, and its associated products, satisfies system requirements allocated to software at the end of each life-cycle activity, solves the right problem (e.g., correctly models physical laws, implements business rules, uses the proper system assumptions), and satisfies the intended use and user needs. (IEEE Standard 1012-2004)

The process of establishing evidence that provides a high degree of assurance that a product, service, or system accomplishes its intended requirements.