And to clarify further, they mean two flip flops in series, not two clocks.
It sort of becomes a short hand to refer to the delay incurred by flip flops in series as "clocks" (short for clock cycles). And to capture data in a flip flop is often referred to as "clocking" the data.
It sort of becomes a short hand to refer to the delay incurred by flip flops in series as "clocks" (short for clock cycles). And to capture data in a flip flop is often referred to as "clocking" the data.