Load testing is a blanket term that is used in many different ways across the professional software testing community.
Load testing generally refers to the practice of modeling the expected usage of a software program by simulating multiple users accessing the program's services concurrently. As such, this testing is most relevant for multi-user systems, often one built using a client/server model, such as web servers. Although you could perform a load test on a word processor by or graphics editor forcing it read in an extremely large document; on a financial package by forcing to generate a report based on several years' worth of data, etc.
When the load placed on the system is accelerated beyond normal usage patterns, in order to test the system's response at unusually high or peak loads, it is known as Stress testing. The load is usually so great that error conditions are the expected result, although there is a gray area between the two domains and no clear boundary exists where you could say that an activity ceases to be a load test and becomes a stress test.
There is little agreement on what the specific goals of load testing are. The term is often used synonymously with performance testing, reliability testing, and volume testing .
See also: software testing
