| Word | Definitions | Synonyms |
|---|---|---|
| aplacophoran | (noun) deep-water wormlike mollusks lacking calcareous plates on the body but having fine slimy spicules on the covering mantle | Synonyms: solenogaster |
| aplasia | (noun) failure of some tissue or organ to develop | - |
| aplite | (noun) light-colored and fine-grained granitic rock consisting chiefly of quartz and feldspars | - |
| aplomb | (noun) great coolness and composure under strain | Synonyms: assuredness, cool, poise, sang-froid |