Prefixes are particularly common in Dutch
surnames. Mostly they are placenames: Van der Graaff
, Van de Graaf
, or any other way to spell it, means 'from the ditch'; Van den Bos
, etc. means 'from the bush' or 'from the woods'.
This is complicated by the fact that many manes of towns are toponyms as well; so Van Beek is likely to refer not just to any 'beek' (creek), but to a particular place known by that name, that may bear the official name of Hilvarenbeek, Vierlingsbeek, Spaubeek, Beek or any other Dutch town whose name ends in 'beek'.
What is also very common is a name that unambiguously refers to a town: Van Meurs, Van Arnhem, Van Gulik, Van Keulen.
This kind of name is particularly common on the south of the Netherlands, Belgium (Flanders), and was once used in adjacent parts of Germany. In Germany, however, this type of name became associated with nobility: any surname with 'von' (Von Lippe zu Biesterfeld) implied a title, so the prefix was dropped from common names in Germany, and the whole type of name disappeared.
There are many other prefixes in Dutch surnames: In 't Veld (in the field), 't Hart (the heart), De Bakker (the baker), Vennegoor of Hesselink ('Vennegoor' or 'Hesselink').
In the Netherlands, the spelling of prefixes in surnames varies with the name, but capitalization and interpunction doesn't, and when sorting names, prefixes are not considered. For example, Van der Beek and Van de Beek are two distinct names, but Vanderbeek is not used, and both names are sorted under the B, before Beekmans.
In Belgium, even spelling and interpunction vary with the name, and sorting considers prefixes; in Belgium, Vander Beek, Vanderbeek and Van der Beek are three different names, all sorted under the V.
Fortunately this isn't the node to discuss prefixes in place names (ranging from 's-Gravenhage to Sint-Job-in't-Goor).
Suffice it to say that some software companies specialize in identifying and sorting address data; their activities are entirely based on sorting out this particular problem for others.