| Term | Definition |
| absquatulate | To make off, decamp, or abscond. |
| acronychal | Happening in the evening or at nightfall. |
| acrophony | The use of a word starting with a letter of the alphabet as the name of the letter. |
| Albertopolis | A group of cultural sites in South Kensington, London. |
| alexpharmic | Having the quality or nature of an antidote to poison. |
| analemmatic | Relating to a scale that shows the seasonal difference between time as shown by clocks and by the sun. |
| anamorphosis | The process of creating an anamorphic image. |
| anatine | Resembling or characteristic of a duck. |
| anfractuosity | A channel, crevice or passage full of windings and turnings. Not describing a maze. |
| ansible | An interstellar instantaneous communications device. |
| anthropodermic | Consisting of human skin. |
| antimacassar | A protective or decorative cloth over the back of a chair. |
| apocope | Leaving out the last sound, syllable, or part of a word. |
| arenaceous | Having the appearance or consistency of sand. |
| astrobleme | An eroded meteor impact crater. |
| astrobolism | The blasting of plants by the sun during high summer. |
| ataraxy | Freedom from disturbance of mind or passion; imperturbability. |
| Atrabilious | Gloomy or morose; bad-tempered or irritable. Is normally used when poetic. |
| Austringer | A keeper of goshawks. |
| Autohagiography | Writing about oneself in an adulatory way. |
| Bafflegab | Incomprehensible or pretentious verbiage. |