A kind of software that emulates user input for load testing / stress testing an application under development.

It can work somewhat like a macro recorder. During setup, the load driver records what a user does when using the application; during testing, the load driver plays back these steps against the applications, but many times, and in several concurrent threads. This simulates a somewhat realistic pattern of heavy usage of the application.

''Alternative definition:'' A software for injection of request that replicates a group of users. This generates volume, concurrency and typing time.