I seem to remember we had an alternative terminology therad here some time ago, but I couldn't be bothered to find it and resurrect it.
Just came out of a meeting with the Release Manager who wants to regress our pre-production environment to a previous release. By a slip of the tongue he said "I want to regret the pre-production environment" to which I responded "and I need to regrettion test it"
So, new term - "Regrettion testing"
It seems so appropriate as we so often do regret doing these things!
Somewhat timely: Sanity (Claus) Testing
I prefer Regressing Testing.
There are times when I feel like I am going backwards especially since I am trying to create tests for enhancments done several years ago.