Cassava flour is a finely-ground flour made from cassava (also called manioc and yuca). It is a gluten-free flour that is very similar to tapioca flour.
Because cassava flour includes the entire tuber, while tapioca flour is made with soluble starch extracted by soaking and pulping, cassava has more fiber and a stronger taste. It is also a slightly more effective thickener. Cassava flour has slightly more thickening power than wheat flour.