Definition of "vitellus" [vi•tel•lus]

• The yolk of an egg. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Si vero fuerit in aestate vitellus avi semper superponatur."
• "This constitutes the vitelline circulation (Fig. 459), and by means of it nutriment is absorbed from the yolk (vitellus.) 5"
• "Special names have been given to these parts of the ovum; the cell-body is called the yelk (vitellus), and the cell-nucleus the germinal vesicle."