from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Formation of the yolk of an egg.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. yolk deposition; the process of yolk formation via nutrients being deposited in the oocyte, or female germ cell involved in reproduction
Harries JE, Sheahan DA, Jobling S, Matthiessen P, Neall P, et al. (1997) Estrogenic activity in five United Kingdom rivers detected by measurement of vitellogenesis in caged male trout.
In fact, the fat body plays a crucial role not only in lipid storage and transport to the hemolymph, but also in lipid biosynthesis from carbohydrates, the biosynthesis of proteins such as antifreeze proteins (AFP) , and yolk deposition in oocytes or vitellogenesis 
Transplantation of ovaries into male Periplaneta americana: effects on vitellogenesis and vitellogenin secretion
These three genes together represented the most significantly enriched biological process, vitellogenesis, in these males (