胚芽是植物种子胚的一部分,由生长点和幼叶组成，与胚茎和胚根共同构成胚轴。胚芽位于胚轴的上端，当种子发芽出土后，将继续发育成产生植物的茎、枝和叶片等构造。禾本科植物种子的胚芽被胚芽鞘包围。

The germ of a cereal is the reproductive part that germinates to grow into a plant; it is the embryo of the seed. Along with bran, germ is often a by-product of the milling that produces refined grain products. Cereal grains and their components, such as wheat germ oil, rice bran oil, and maize, may be used as a source from which vegetable oil is extracted, or used directly as a food ingredient. The germ is retained as an integral part of whole-grain foods. Non-whole grain methods of milling are intended to isolate the endosperm, which is ground into flour, with removal of both the husk (bran) and the germ. Removal of bran is aimed at producing a flour with a white rather than a brown color, and eliminating fiber: neither of these objectives is desirable from the nutritional viewpoint. Germ is rich in polyunsaturated fats (which have a tendency to oxidize and become rancid on storage) and so germ removal improves the storage qualities of flour.