Washington state divorce law what is pro tonk?

I believe that you mean "Nunc Pro tunc" which pertains to divorce papers that were improperly (or never) filed by either the court or a party of the divorce. (after the interlocutory judgment has been granted), the result being that the parties to the divorce were never actually divorced or rather that the divorce never became final. In a case such as this, if one of the parties actually got married after they percieved that they were divorced, later finding out that they were never divorced, then they would petition the court originaly hearing the case to issue a "nunc pro tunc" order to grant the divorce retroactive to the earlier date.

The literal meaning of Nunc Pro Tunc is "now for later" (latin)