|Burn-in is a common term in the electronics industry and is the holding of an electrical device at an elevated temperature for a specified number of hours, generally with bias and an electrical load applied. (Bias is the application of an external d.c. voltage to set the upper and lower operating limits of a device) This is done in an attempt to stress all elements of the device at maximum rated operating conditions in order to reveal all stress and time dependent failure modes. In effect, burn-in is an accelerated aging process and is used particularly for semiconductor devices such as transistors, integrated circuits, etc.
Source: FDA website
A test which involves running a system or device for a period of time to ensure that all components are working properly.
Source: Defense Industrial Base Assessment: Counterfeit Electronics prepared by the U.S. Department of Commerce, Bureau of Industry and Security, Office of Technology Evaluation