Khorasan (Triticum turgidum subsp. turanicum) is an ancient form of wheat, named after the historical region of what is now Iran. Grains of Khorasan are larger than modern wheats and it is enjoyed for its rich, nutty flavour. It is a good source of protein, fibre, vitamins and minerals.
You may find Khorasan flour listed under its commercial name of Kamut flour.
Read more about khorasan in this article.