tussenvoegsel

— A tussenvoegsel, in Dutch linguistics, is a word that is positioned between someone's given name and surname, but is still a part of someone's last name. In the Netherlands, the tussenvoegsels strictly speaking are not a part of someone's last name. For example, someone whose family name is "De Vries" isn't found at the letter "D" in the telephone directory but at "V". Tussenvoegsels are therefore also required to be listed separately in databases; […] In the Netherlands, the tussenvoegsel is written with a capital letter if no name precedes it.