Any test performed with normal or extreme volumes of data, or numbers of users, typically to show stress and performance characteristics and reveal load-related defects.
Comment
Load testing is closely linked with, and may be considered an extension of, Performance Testing. During Load testing, the system will be set up with large volumes of data that will simulate an extraordinary load being placed on the system. A classic example of such a load spike is testing the 'logging in' of users to a system following a fire drill.