Zijlstra

Zijlstra is a last name of a person, which means it's the name that people call someone to identify them as part of their family. Just like your last name is the name that people call you to identify you as part of your family. It's like when you say "I am Timmy Smith" or "I am Sarah Jones," the last name is the part that comes after your first name that tells people which family you belong to. So, when someone talks about Zijlstra, they are talking about a person with that last name, just like when they talk about you or your friends with your last name, they are talking about you or your friends.