Van Der是一个姓氏的前缀。
wiki中提到：“Van is a very common prefix in Dutch language surnames … The most common cases of this are van de, van der and van den”(https://en.wikipedia.org/wiki/Van_(Dutch))
另外知乎上也有说（van der 是什么意思？ - TK语言私教的回答 - 知乎 https://www.zhihu.com/question/284416848/answer/438434316 ）