A thread is a the entity within a process that Windows schedules for execution. A thread has:
• The contents of a set of CPU registers representing the state of the processor.
• 2 stacks, 1 for the thread to use in kernel mode, and 1 for user mode.
• Private storage called Thread Local Storage for use by subsystems, runtime libraries, and DLLs.
• A thread ID.
Threads sometimes have their own security context.