Validation
After final release, the validation stage checks whether requirements relating to a specific intended use of a software component or application have been fulfilled (ISO 9000).
Verification
In ISO 9000 terminology, this refers to checking a software in development against orginal specification documentation.
In development jargon, it means using mathematical formulae to prove that a component or application works as intended.
Version
A version of a software application is the state of the code at a definied point in time. Usually, versions are named numerically in series (e.g. 8.1.9).
Cf. version on Wikipedia.
V-model
Refers to a framework for software development whose aim is to describe development as a complete life-cycle starting at an analysis of requirements and going through to acceptance, use and maintenance.
The V-model sets checks and tests for each phase it describes. It describes how components and versions produced before the end of the project can be tested, verified and validated.
There are now several versions of the model, such as v-model 97 and v-model XT.
Cf. Wikipedia on v-models.
Volume testing
This approach to testing works with large volumes of data which are fed into the test object to see whether it copes. As such, this is a form of stress testing.
Precondition
Refers in terms of software programming to the system state and ideal test environment necessary before a test case or suite can be executed.
See Wikipedia: precondition.