Skip to definition.
Get the FREE one-click dictionary software for Windows.


Noun: yolk sac
  1. Membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
    - vitelline sac, umbilical vesicle, vesicula umbilicus
     
  2. Membranous structure enclosing the yolk of eggs in birds, reptiles, marsupials, and some fishes; circulates nutrients to the developing embryo

Derived forms: yolk sacs

Type of: sac

Encyclopedia: Yolk sac

Nearest

yoicks
yoke
yokefellow
yokel
yokelish
yokel-like
Yoko Ono
Yokohama
Yokuts
yolk
yolk sac
yolked
yolky
yom
Yom Kippur
Yom Kippur War
yon
yond
yonder
yoni
yonks