- 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.
More definitions of yolk sacDefinition of yolk sac in:
- The British & World English dictionary