What's the difference between flight level and pressure altitude?
Flight Level specifically refers to Pressure Altitude in 100 foot increments within the Standard Pressure Region, which in North America starts at 18000 ft and above, and at various lower altitudes elsewhere.  

If you are in the Altimeter Setting Region where you set local barometric pressure to get indicated altitude, you normally use indicated altitude and could state the pressure altitude if asked, but you wouldn't use the term Flight Level.