| abbreviation |
a shortened form of a word or phrase used in writing. |
| ad |
a short form of "advertisement," a public notice that tells people about products for sale, events, employment opportunities, or the like. |
| addend |
a number or amount added to another to form a sum. |
| aerobics |
(used with a singular or plural verb) a form of exercise that works the heart and lungs to help the body use oxygen better. Running, swimming, biking, or dance are forms of aerobics. |
| alga |
singular form of "algae." |
| 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 algae. "Algae" is a plural noun; the singular form is "alga." |
| algebra |
a form of mathematics used to solve problems in which some of the numbers are not known. In an algebra problem, letters stand for the unknown numbers. |
| am |
a form of the verb "be" that is present tense and used with the pronoun "I." |
| arcade |
a row of arches connected to form a passageway. [1/2 definitions] |
| arch1 |
to form an arch or curve in. [2/4 definitions] |
| are1 |
a form of the verb "be" that is present tense and used with the pronouns "you," "we," or "they." It is also used with plural nouns. |
| aren't |
shortened form of "are not" and of "am not." |
| assembly |
a collection of parts put together to form a whole, as in a machine. [2/4 definitions] |
| auto |
short form of "automobile," a vehicle powered by a motor that uses gasoline or other fuel; car. |
| 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. |
| ballet |
a form of dance that uses exact, graceful movements. [1/2 definitions] |
| bangle |
a bracelet in the form of a solid ring. |
| bank1 |
to form into a pile. [1/3 definitions] |
| bend |
to cause to take on a curved or angled form, or a different form. [2/5 definitions] |
| beryllium |
a hard, light, gray substance that is one of the chemical elements. Beryllium is sometimes combined with other elements to form an alloy. It is also used in building rockets. (symbol: Be) |
| Big Dipper |
part of the constellation Ursa Major, made up of this constellation's seven brightest stars. These stars form a shape that looks like a ladle, or dipper. |