what does the "von" mean?

[Gilbert von Studnitz]

The basic designation of the German nobility is the predicate "von", which
the great majority of such houses carry. There are a small number of noble
houses, almost exclusively of the Uradel (ancient nobility) which have never
used the "von" or any other noble predicate but are nevertheless of fully
equal standing with those that do. In northern and eastern Germany there are
a substantial number of families that use the "von" as designations of the
towns or areas they came from (as is the case with the older noble families)
but that have never been noble and make no pretense to be so. A few nobles
houses use "von und zu" meaning they are not only from the place mentioned
but still retain it. In post-WWII years many houses were unable to retain the
estates the "zu" referred to (especially in the East) but still use it as
part of their name. Other noble predicates sometimes seen are "von dem", "von
der", or "vom". There is even one old noble family named Winckel which uses
"aus dem" instead of "von". All of these essentially mean "from".