/ə-ˈrē-nə/
[ UNIX ]
n. The area of memory attached to a process by 'brk(2)' and 'sbrk(2)' and used by 'malloc(3)' as dynamic storage.
So named from a semi-mythical 'malloc: corrupt arena' message supposedly emitted when some early versions became terminally confused.
See overrun screw, aliasing bug, memory leak, smash the stack.