| A | B |
| Anthology- | a collection, especially of literary works |
| Anthropomorphic- | ascribing human characteristics to nonhuman animals or objects |
| Antipodal- | situated on opposite sides of the earth; exactly opposite |
| Antiquity- | ancientness; ancient times |
| Aperture- | an opening |
| Apex- | highest point |
| Apogee- | the most distant point in the orbit of the moon or of an artificial satellite |
| Apoplexy- | stroke |
| Apostasy- | abandonment or rejection of faith or loyalty |
| Appalling- | causing horror or consternation |