| abalone |
a large sea snail that has several shiny colors on the inside of its shell. Abalone are mollusks. People eat abalone meat and make decorations from the shells. |
| air conditioning |
a system that cools air and takes dust and dampness out of it. Air conditioning is used inside buildings and cars. |
| 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. [1/2 definitions] |
| annual ring |
one of the rings of wood on the inside of a tree that can be seen when the tree is cut into logs. Each ring represents a year of growth. |
| arctic |
(often capitalized) the region around the North Pole and inside the Arctic Circle. [1/3 definitions] |
| arthropod |
a large group of animals with hard shells on the outsides of their bodies, legs with joints, and no bones inside their bodies. Insects, spiders, centipedes, and crabs are arthropods. |
| atrium |
a courtyard inside a building, either open to the sky or with a glass ceiling. [1/2 definitions] |
| be on to |
(informal) to have inside information about. |
| 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. |
| bladder |
an organ inside the body that collects urine. The bladder gets larger when it fills and smaller when it becomes empty. |
| brain |
the organ inside the skull of humans and animals. The brain is the main part of the central nervous system. It controls the body's movements and activities and is the center of thought, memory, and feelings. [1/3 definitions] |
| camera |
a device for taking photographs. A camera is a closed box with a small hole that allows light to reach the film inside. The light makes images on the film. |
| cassette |
a case with film, audio tape, or video tape inside. Cassettes make it easy to load a camera or recorder. |
| castle |
a large, strong building where a noble lived with his family and servants. Many castles were built long ago to defend the people inside against attacks. [1/2 definitions] |
| ceiling |
the top inside surface of a room. [1/3 definitions] |
| chestnut |
a nut that grows inside a prickly shell. It has a sweet taste. [1/4 definitions] |
| cloister |
a covered walk around the inside of a building that faces an open central courtyard. [1/2 definitions] |
| come out |
to move from a position inside or partially inside something. [1/5 definitions] |
| concave |
curved inward like the inside of a bowl. (Compare with "convex.") |
| cram |
to force into a space that is too small; stuff. (usually followed by "inside," "into," or "down.") [1/3 definitions] |
| crater |
a hollow area shaped like the inside of a bowl. The mouth of a volcano is a crater, and the moon has many craters on its surface. |