The abbreviation mr stands for meester in de rechten or master of law and is the official form of address for anyone, male or female, who has the title. So do not be surprised to see a letter from mr. Nicola Smit or the like. If you are addressing several meesters, the form of address is mrs. Nicola Smit and Jan Groen – which is even more confusing. The Dutch short form of Mrs is Mw.