| absorb |
When something absorbs another thing, it takes it into itself. It soaks it up. If something absorbs water or other liquid, it takes it into itself the way a towel or sponge does. [1/2 definitions] |
| acid |
a chemical substance that dissolves in water, has a sour taste, and turns blue litmus paper red. [1/4 definitions] |
| afloat |
on the water; floating. |
| alga |
"Alga" is the singular form of the word "algae." Algae are living things that live mainly in water and make their food by using light from the sun. Algae are similar to plants, but they are not usually considered to be plants because they are different in some ways. For example, algae don't have roots and leaves like plants do. Most forms of algae are very helpful for animals and people. Seaweed is a kind of algae, which many people eat and can also be used in making other things. Fish and other water animals use algae for food. |
| algae |
organisms that live mainly in the water and make their food through photosynthesis. Algae are different from plants in that they have no true leaves, roots, or stems. Seaweeds are one form of algae, but there are many others, including a large number that cannot be seen without a microscope. "Algae" is the plural form of the word "alga." |
| alligator |
a large reptile with short legs, a long body and tail, and a long, wide snout. Alligators are protected by thick skin with many hard bumps. They live in rivers, lakes, swamps, and other bodies of water in the southeast United States and in China. They usually eat insects, fish, turtles, snakes, birds, and other water animals, but have been known to attack small land mammals. They are closely related to crocodiles. Chinese alligators are endangered because their habitat is being changed by people. |
| ammonia |
the liquid made from mixing ammonia gas with water. Certain cleaners are made with ammonia. [1/2 definitions] |
| amoeba |
a tiny living thing made of only one cell. Amoebas move by changing their shape. They eat by wrapping their bodies around their food. Amoebas live in fresh and salt water, soil, and in animals. Most kinds of amoebas can only be seen through a microscope. |
| amphibian |
a small animal that spends part of its life cycle in water and part of its life cycle on land. Amphibians hatch in water and breathe with gills. Then they develop lungs so the adults can breathe air. Amphibians are cold-blooded animals with skeletons inside their bodies. Frogs, toads, and salamanders are amphibians. [2 definitions] |
| amphibious |
able to live both on land and in water. [2 definitions] |
| anchor |
An anchor is a heavy piece of iron or other metal that is attached to a boat or ship. When people want to keep a boat from moving, they drop the anchor into the water. [2/4 definitions] |
| antifreeze |
a substance that lowers the freezing point of a liquid such as water. |
| aquaculture |
the farming of plants and animals that live in water. |
| aquarium |
a tank or other container filled with water in which water animals and plants are kept. [2 definitions] |
| Aquarius |
a constellation located between Capricorn and Pisces. Aquarius is also called the Water Bearer. [2/3 definitions] |
| aquatic |
of or taking place on the water. [2 definitions] |
| aqueduct |
a channel or pipe built to carry water over a long distance. [1/2 definitions] |
| aquifer |
a layer of rock, sand, or gravel that contains water from which wells and springs are supplied. |
| Arabian Sea |
The Arabian Sea is a large body of water that lies between India and the countries of Oman and Yemen. The Arabian Sea is part of the Indian Ocean. |
| Aral Sea |
formerly, a very large, single lake in Central Asia. Once one of the world's largest lakes, the Aral Sea has lost a great deal of its water in recent times and it has divided into separate parts. The southeastern part of the Aral Sea has become entirely dry and is called a desert now. |
| Arctic Ocean |
The Arctic Ocean is one of the five oceans of the world. An ocean is a large body of salt water that covers a very large part of the earth. The Arctic Ocean is in the most northern part of the world and it is very cold and icy. If you look at a map, it is above Canada, Russia, and other far northern countries of the world. |