English noun: amniotic sac | |||
| 1. | amniotic sac (animal) thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals) | ||
| Synonyms | amnion, amnios | ||
| Broader (hypernym) | sac | ||
| Part meronym | amniote, fetal membrane | ||
| Domain category | mammal, mammalian | ||