The yellow part of an egg; the vitellus. [1913
Webster]
(Zool.) An oily secretion which naturally covers
the wool of sheep. [1913 Webster] Yolk cord
(Zool.), a slender cord or duct which connects the yolk glands with
the egg chambers in certain insects, as in the aphids. Yolk gland
(Zool.), a special organ which secretes the yolk of the eggs in
many turbellarians, and in some other invertebrates. See Illust. of
Hermaphrodite in
Appendix. Yolk sack
(Anat.), the umbilical vesicle. See under Unbilical. [1913
Webster]
Yelk \Yelk\, n. Same as Yolk. [1913 Webster]