Legal Question in Family Law in California

No idea. I'm assuming you are looking at online case information from the clerk's office. You'll have to call them and ask them what their abreviations mean.

It means that one party filed a Declaration of Service of the Preliminary Declaration of Disclosure in a case for dissolution of marriage. The parties are required to serve each other with declarations of disclosure, but not file those with the court. The only thing that gets filed with the court is the declaration of service, showing the court that the preliminary declaration of disclosure was served on the other party.