| bacterium |
singular form of "bacteria." Bacteria are tiny living things made up of one cell each. Bacteria live in most living things and in all parts of the earth. Most bacteria are useful to people, but some are harmful because they can cause disease. |
| badge |
a pin, patch, or ribbon people wear to show that they belong to a group, have a particular job, or have done something special. |
| badger |
a furry mammal with short legs and a long body. The American badger has a white stripe on its forehead that runs down its back, and it has long dark marks on its face also. Badgers eat worms, rodents, rabbits, and plants. Different kinds of badgers live in Europe, Asia, and North America. They are related to skunks, otters, and other kinds of weasels. [1/2 definitions] |
| bandit |
a robber who is often a member of a gang that robs people while they are travelling. |
| barnacle |
a small sea animal that attaches its shell to rocks, the bottom of ships, docks, and other objects in shallow parts of the ocean. Barnacles float freely in the ocean when they are young. They develop shells with sharp edges as adults. Barnacles are kinds of crustaceans. |
| bat2 |
a small mammal that flies. Bats have small bodies and large wings covered with skin. Most bats eat at night, when they use sound to find and catch flying insects. Bats are found in most parts of the world. There are around one thousand kinds of bats. Their wingspans range from less than two inches to more than five feet. Some kinds of bats live in large colonies that roost in caves or in a section of forest. |
| bear2 |
a large furry mammal with a short tail. Bears are omnivorous; they may eat plants, honey, insects, fish, and small mammals. There are several kinds of bears, including black bears, brown bears, grizzly bears, and polar bears. |
| beaver1 |
a large rodent, up to four feet long, with thick brown fur and a wide flat tail. Beavers use their long front teeth to cut down trees for food and to build dams and lodges (beaver houses). They use the dams to keep water around their lodges. Beavers live in North America, Europe, and Asia. |
| bighorn |
a wild sheep found in the Rocky Mountains of North America. The male has large, curved horns; the female has short, straight horns. They are also called Rocky Mountain sheep. |
| bison |
a very large mammal with a large head, humped shoulders, and short curved horns. Bison used to roam the plains of North America in large herds, but they were hunted until they were almost extinct. North American bison are also called buffalo, but they are not related to the true buffalo of Africa and Asia. Bison have hooves and are closely related to cattle. Bison eat only plants and chew their cud. [1/2 definitions] |
| black bear |
a medium-sized bear, usually with thick black or reddish brown fur. They are the most common bears in North America and live in forests and mountain areas. [1/2 definitions] |
| blog |
a journal posted on a website that someone regularly write entries in. When people have a blog, they write about personal experiences or opinions, or about particular topics they have special knowledge of or are interested in. The word "blog" is a short form of "Web log." |
| bloodhound |
a breed of dog. Bloodhounds are large dogs with baggy skin and long, drooping ears. They have an excellent sense of smell and are used to track people or animals. |
| blue whale |
a mammal that lives in the ocean. Blue whales are the largest kind of animal that has ever lived. They can grow up to 100 feet long and weigh up to 150 tons. Their large mouths have baleen instead of teeth. Blue whales use baleen to filter lots of very small food such as shrimp from ocean water. |
| bluff2 |
to lead other people to believe that the cards in one's hand are better or worse than they really are. Bluffing is a strategy used in the game of poker. [1/3 definitions] |
| boa constrictor |
a large snake that lives in the tropical areas of Central and South America. Boa constrictors are pale brown with darker marks and are not poisonous. They kill their prey by winding around it and squeezing it until it cannot breathe. |
| bobcat |
a wild cat with red-brown fur, tufted ears, and a short tail. Bobcats are about twice the size of a house cat. They are a kind of lynx and live in southern Canada, the United States, and Mexico. Bobcats are carnivorous mammals. |
| boll weevil |
a small beetle with a gray body and a long snout. It lays eggs in the seed pods of the cotton plant where they hatch and cause much damage to crops. |
| bracket |
one of a pair of punctuation marks ([ ]). They are used to enclose words or numbers. [1/5 definitions] |
| brontosaur |
a huge dinosaur that only ate plants. Brontosaurs had heavy bodies and very long necks and tails. They lived over 100 million years ago. Brontosaurs are now called apatosaurs by scientists who study dinosaurs. |
| brotherhood |
a warm and close feeling between brothers or between people who feel like they are family. [1/2 definitions] |