Radi is a German word for horseradish
Andere /Weitere Definition:
Radi is the Viennese term for horse radish. Fresh Radi is thinly grated and is often served with pork dishes, such as Sauerbraten, Tafelpitz and Spannferkel.
Spicy Radi or horse radish is mostly grown in the South Eastern Austrian region of Styria.
Radi (Armoracia rusticana) is also called Rettich, Kren, Rachenbeißer and Meerrettich in German.
Personal Note: I lived in Austria for almost three (3) months and with the family where I lived in Lower Austria, whenever they have a visitor, I am always asked to grate fresh Radi . They serve freshly grated Radi for breakfast, brunch or dinner whenever they have a guest with hams and sausages. I only tasted one time freshly grated Radi in one Austrian restaurant when I ordered Tafelpitz and I enjoyed it even if it is spicy with my Tafelpitz.
List of books: Radi