Definition of yolk sac in English:

yolk sac

Syllabification: yolk sac

noun

Zoology
  • 1A membranous sac containing yolk attached to the embryos of reptiles and birds and the larvae of some fishes.
    More example sentences
    • The eggs take about 20 weeks to hatch and the now free-swimming ray is still reliant upon its yolk sac for a few more weeks before it begins to feed upon shrimps.
    • Likewise, the occasional yolk sac tumor arising in liver has been reported in childhood.
    • The neoplasm metastasized as the yolk sac component.
  • 1.1A sac lacking yolk in the early embryo of a mammal.

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Word of the day maelstrom
Pronunciation: ˈmeɪlstrəm
noun
a powerful whirlpool in the sea

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