aplacental
— Adjective
– English
~ having no placenta; "monotremes and marsupials are aplacental mammals"
Aplacophora
— Noun
– English
~ an order of Amphineura
aplacophoran
— Noun
– English
~ deep-water wormlike mollusks lacking calcareous plates on the body but having fine slimy spicules on the covering mantle
aplanatic
— Adjective
– English
~ free from or corrected for spherical aberration; "an aplanatic mirror"
aplasia
— Noun
– English
~ failure of some tissue or organ to develop