n. 1. A factory test designed to catch systems with marginal components before they get out the door; the theory is that burn-in will protect customers by outwaiting the steepest part of the bathtub curve (see infant mortality).
2. A period of indeterminate length in which a person using a computer is so intensely involved in his project that he forgets basic needs such as food, drink, sleep, etc.
Warning: Excessive burn-in can lead to burn-out.