segmentation fault
segmentation fault: n. [Unix] 1. [techspeak] An error in which
a running program attempts to access memory not allocated to it and
core dumps with a segmentation violation error. This is often
caused by improper usage of pointers in the source code,
dereferencing a null pointer, or (in C) inadvertently using a
non-pointer variable as a pointer. The classic example is:
int i;
scanf ("%d", i); /* should have used &i */
2. To lose a train of thought or a line of reasoning. Also uttered
as an exclamation at the point of befuddlement.