Reiatsu = outside body, in use.
Reiryoku = inside body
That's the quick and dirty version anyway. When I said free flowing reiatsu, I refer to the exhaust of any given ability. In other words, anything not being in current use. Reiatsu isn't recycled. It goes somewhere after use whether it is an attack that is fired or hardening yourself to increase your defense or to coat a weapon to increase your attacking power. Therefore, after the use ends, it ceases to have a job and returns to the air which I'm layman dubbing free flowing reiatsu.
Seeing as there is no canonical term that covers outside body, not in use, I simply created a layman term based upon its last known job. If you have a canonical term that covers it that I'm unaware of, be all means let me know.
