Yolk sack

(Anat.) the umbilical vesicle. See under Unbilical.

See also: Yolk

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
Histologically, GCTs are classified as germinomas, embryonic carcinomas, yolk sack tumors, malignant mixed GCTs and malignant teratomas.
Between the two of them, we'll have total solar energy in our lifetime, and we will fulfill what Buckminster Fuller [a futurist who wrote Operating Manual for Spaceship Earth] said: that we'll eventually have to come out of the egg and quit living on our yolk sack and start living off of what created all our fossil fuels--the sun.
They'll be fine in the incubator for a day or so--the residual yolk sack will sustain them, no problem.