Long story short, I have a church program in front of me.  The “postlude” to the service is “Prelude In Classic Style.”  There is a post-it note attached asking, “If a prelude is used as a postlude does it become a postlude?”

The answer?  Apparently not.  The explanation we got FROM NATE was essentially that a prelude is where it appears in the original piece of music which doesn’t change if it is used by itself in a different setting.

Thus, feel free to use pre- and postludes all willy-nilly without fear of changing their definitions!