Cassava roots are a type of tuberous root that many people eat. Although cassavas are rare in most developed nations, they are a major food staple throughout sub-Saharan Africa and Southeast Asia due to their hardiness and caloric content. It’s estimated that 10% of the world relies on cassavas as their primary food staple. It’s clearly an important plant.
They are very starchy roots. The starch derived from cassava roots is actually familiar to virtually all people in the Americas as “tapioca”. Although tapioca pudding is a dish famous around the world, cassavas themselves are not very sweet. They are quite similar to yams, though containing more calories.
Like yams, cassavas are vegetables. They are not sweet; they are durable; they are always cooked before being eaten; and, mostly definitively, they are roots, not the fruit of the cassava plant. Something has to be a fruit botanically for it to be one culinarily.