1) Food 2) Nutrient 3) Yolk 1) Yolk 
yolk of an egg
• (n.) Perisperm in an early condition. • (n.) The contents or substance of the ovum; egg yolk. See Illust. of Ovum.
1. <biology> The contents or substance of the ovum; egg yolk. ... 2. <botany> Perisperm in an early condition. ... Origin: L, the yolk of an egg. ... (01 Mar 1998) ... 
(vi-tel´әs) yolk.
Vi·tel'lus noun [ Latin , the yolk of an egg.] 1. (Biol.) The contents or substance of the ovum; egg yolk. See Illust. of Ovum . 2. (Botany) Perisperm in an early condition. 
Type: Term Pronunciation: vī-tel′ŭs Synonyms: yolk1
vitellus The yolk of an egg. The word vitellus was first used in the sense 'yolk of an egg', by Aulus Cornelius Celsus, a Roman physician and writer of the early first century.