蛋黄
Vitellus \Vi*tel"lus\, n. [L., the yolk of an egg.] 1. (Biol.) The contents or substance of the ovum; egg yolk. See Illust. of {Ovum}. 2. (Bot.) Perisperm in an early condition.
vitellus n : nutritive material of an ovum stored for the nutrition of an embryo (especially the yellow mass of a bird or reptile egg) [syn: {yolk}] [also: {vitelli} (pl)]