amniote

noun

1. any vertebrate of the group Amniota, comprising the reptiles, birds, and mammals, characterized by having an amnion during the embryonic stage.

noun

1. any vertebrate animal, such as a reptile, bird, or mammal, that possesses an amnion, chorion, and allantois during embryonic developmentCompare anamniote

1. Any of the vertebrates that have an amnion during embryonic development. Reptiles, birds, and mammals are amniotes.