Dictionary.net

A program execution errorwhich is trapped by the operating system and which resultsin abrupt termination of the program.It may be possible for the program to catch some such errors,e.g. a floating point underflow; others, such as aninvalid memory access (an attempt to write to read-only memoryor an attempt to read memory outside of the program's addressspace), may always cause control to pass to the operatingsystem without allowing the program an opportunity to handlethe error. The details depend on the language's run-timesystem and the operating system.See also: fatal error.