Voorschreven (literally: before written) means “aforesaid.”
You may come across the term in notarial or court records. If someone is mentioned as “Jan Jansen, voorschreven” it means it is not just any Jan Jansen, but the Jan Jansen whose identity was established earlier in the document.

Office of the notary. Jan Woutersz. Stap, ca. 1629. Credits: Rijksmuseum