We have specific language specified in our manuals for communicating turbulence severity to our F/As. I don't believe they get any more training than that in the definitions. They may, or may not, pick up more as they do the job for a while. Their understanding of the full definitions of each stage will not always be completely accurate. They know what they need to know to do what they need to do based on the information we give them.

That said, turbulence forecasting and reporting is more art than science. We have many tools showing forecast and reported turbulence and it isn't unusual for them all to disagree to some extent. We may know that there is the potential for moderate turbulence, and brief the purse on that, but will then do what we can to avoid it so we may never experience the turbulence that we were expecting.