Although granular, couscous is a processed grain product rather than a cereal grain.
It's traditional to North African cooking but also used in other regions once occupied by the Moors. That sold in Britain is typically fine grained and made from wheat, however couscous can authentically be made from millet, barley and corn. Israeli couscous is a large variety rather like beads.
The word couscous is also used to describe the complete dish of spicy stew and accompanying grain of which the product couscous is part.
The traditional method of steaming, rubbing and steaming again may seem laborious but it really is the best way to produce light, perfectly separate grains. A quick method is to rehydrate the grains in boiling water and fluff them up with a fork.
Couscous can be used in salads, or served as a dessert or breakfast dish with almonds, milk, sugar and cinnamon.