Merriam-Webster's Collegiate® Dictionary, 11th Edition
CEREAL
I. adjective
Etymology: French or Latin; French céréale, from Latin cerealis of Ceres, of grain, from Ceres
Date: 1818
relating to grain or to the plants that produce it,
II. noun
Date: 1832
a plant (as a grass) yielding starchy grain suitable for food, a prepared foodstuff of grain (as oatmeal or cornflakes)