| A | B |
| aster/astro | root meaning "star" |
| audi | root meaning "to hear" |
| asteroid | one of the tiny planets in our solar system |
| asterisk | a symbol shaped like a star (*) |
| astrology | the study of the possible influence of the stars on people in order to predict the future |
| astronaut | a person who travels in space |
| auditory | having to do with hearing |
| audible | loud enough to be heard |
| audience | the group of people attending or listening to a movie, a concert, or a play |
| audiovisual | involving the use of both sight and sound |
| audition | a trial performance in which a musician or actor is heard and evaluated |
| auditorium | a large theater or concert hall |
| astronomy | the science of the planets and stars |