| A | B |
| aqualung | breathing equipment for underwater swimming or diving |
| aquamarine | a bluish sea-green color |
| aquaplane | a wide board that is towed by a motorboat, like a single water ski |
| aquarium | an artificial pond or tank of water where live water animals and water plants are kept, a building where such collections are exhibited |
| aquatic | growing or living in water |
| aqueduct | a channel that carries large amounts of water |
| Aquarius | a constellation outlining a man pouring water from a container; the 11th sign of the zodiac |
| aqueous | watery |