from
The Free On-line Dictionary of Computing (8 July 2008)
program counter
<hardware> (PC, or "instruction address register") A
{register} in the {central processing unit} that contains the
addresss of the next instruction to be executed. The PC is
automatically incremented after each instruction is fetched to
point to the following instruction. It is not normally
manipulated like an ordinary {register} but instead, special
instructions are provided to alter the {flow of control} by
writing a new value to the PC, e.g. JUMP, CALL, {RTS}.
(1995-03-21)