Wash. Rev. Code § 84.09.020
In all proceedings relative to the levy, assessment or collection of taxes, and any entries required to be made by any officer or by the clerk of the court, letters, figures and characters may be used to denote townships, ranges, sections, parts of sections, lots or blocks, or parts thereof, the year or years for which taxes were due, and the amount of taxes, assessments, penalties, interest and costs. Whenever the abbreviation "do." or the character "''" or any other similar abbreviations or characters shall be used in any such proceedings, they shall be construed and held as meaning and being the same name, word, initial, letters, abbreviations, figure or figures, as the last one preceding such "do." and "''" or other similar characters.
RCW 84.09.020