What is Real Power (AC circuit)?
Real power P in W is consumed by the circuit.  


A resistor converts electrical energy into heat.
A lamp converts electrical energy into light and heat.
A motor converts electrical energy into mechanical energy.


Real power does something useful, so the name Real or True power.  

We also need reactive (what you are calling Active) power to make some circuits work.  Motors and Fluorescent lights have magnetic circuits, which require lagging reactive power Q in VAR.  Reactive power is not consumed but goes back and forth between the source and the load.   Reactive power is stored in magnetic fields of inductors (and electric fields of capacitors) and returned to the source as field is collapsed.

Apparent power S in VA is the full impact of the circuit on the source.  All three powers are related by the power triangle.



Real is useful power but the source has to put in apparent power, so the power factor is a kind of efficiency in a circuit.
$$ pf = \frac P S $$
We do power factor correction (add capacitors [leading reactive power] in parallel with the load) to improve the power factor of large loads with poor power factors.