What is a mirco dose?

Is 5 mg THC or 10 still considered a micro dose? And does as you get a tolerance, does that change? I started taking 5 to 10 mg and it has helped my pain and anxiety so much. I took some (gummie) before a yoga class, and I was able to really concentrate on the stretches. I have seen folks smoke up before lifting weights, too. 20 mg gets me high as he'll btw. Not sure the perfect dose for me.