Nau'ukan siril daban-daban da abubuwan da aka hada daga gare su. Siril itace duk wani abinci nadaga cikin hatsi (botanically, wani nau'in kayan ice, da ake kira da caryopsis) wanda ake noma a ciyawa, yahada da endosperm, germ, da kuma bran. Hatsin abinci ana shuka su da yawa dan samar da abinci da dama domin samun karfi ga jama'a ako'ina dake duniya fiye da kowane irin kayan abinci kuma sun kasance staple crops. Edible grains from other plant families, such as buckwheat (Polygonaceae), quinoa (Amaranthaceae) and chia (Lamiaceae), are referred to as pseudocereals. In their natural, unprocessed, whole grain form, cereals are a rich source of vitamins, minerals, carbohydrates, fats, oils, and protein. When processed by the removal of the bran, and germ, the remaining endosperm is mostly carbohydrate. In some developing countries, grain in the form of rice, wheat, millet, or maize constitutes a majority of daily sustenance. In developed countries, cereal consumption is moderate and varied but still substantial. cite web|url=https://www.idrc.ca/en%7Ctitle=IDRC - International Development Research Centre|website=|deadurl=no|archiveurl=https://web.archive.org/web/20160609075145/https://www.idrc.ca/en%7Carchivedate=9 June 2016|df=dmy-all