| biology |
the science that studies the growth and life processes of living things. |
| bioluminescence |
light given off naturally by certain kinds of insects, fish, or bacteria. The bioluminescence of fireflies allows them to blink on and off in the dark. |
| biomass |
the total amount of living things in a particular environment, measured by mass per unit of area or volume. |
| biome |
a major type of global region, such as forest, desert, or grassland, characterized by the community of plants and animals that have adapted to life under the particular soil and climatic conditions that a particular region presents. |
| bionic |
an electronic or mechanical device that replaces or helps something natural. An artificial leg is one kind of bionic device. |
| biplane |
an early type of airplane with two sets of wings mounted one above the other. |
| birch |
a tree or shrub with hard wood and smooth bark that can be peeled off. |
| bird |
an animal with two wings, two feet, and a body covered with feathers. Most birds can fly. Birds are warm-blooded animals with skeletons inside their bodies. Birds lay eggs with hard shells. Robins, eagles, chickens, and ostriches are a few of the many kinds of birds. |
| birdhouse |
something constructed by humans as a place for a bird to build its nest. A birdhouse often looks like a small, simple house. |
| birds of a feather |
a group of people who have similar interests, values, opinions, or backgrounds. (from the expression "Birds of a feather flock together.") |
| birth |
the act or fact of being born. [3 definitions] |
| birthday |
the calendar day and month of one's birth, usually celebrated each year as that date occurs. |
| birthmark |
a mark or mole on the skin present from birth. |
| birthplace |
the place of birth or origin of a person, idea, or movement. |
| birthright |
a right, privilege, or property to which one is entitled by birth. |
| biscuit |
a small, round-shaped bread for one person made with baking powder or baking soda instead of yeast. Biscuits are not usually sweet. [3 definitions] |
| bisect |
to cut or split into two equal parts. [2 definitions] |
| bishop |
a clergyman who holds a high position in certain Christian churches. A bishop is often in charge of a group of churches. [2 definitions] |
| 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. [2 definitions] |
| bit1 |
the metal part of a bridle that is placed in the mouth of a horse and used to control it. [2 definitions] |
| bit2 |
a small amount; little piece. [2 definitions] |