| abbreviate |
When you abbreviate a word, you use a shorter form of it, You often use just a few letters of the word to stand for the whole thing. We often abbreviate things like the names of months, names for the days of the week, and words in addresses like "Street" and "Road." [1/2 definitions] |
| abbreviation |
a shortened form of a word or phrase used in writing. |
| abstract |
When something is abstract, it doesn't have any physical form. Feelings and ideas are abstract things. They are things, but you can't see them or touch them or even smell them! They exist in people's minds only. [1/3 definitions] |
| 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. |
| alliance |
When different people or groups form an alliance, they come together because they have the same goal and they agree to work together to reach that goal. |
| am |
a form of the verb "be" that is present tense and used with the pronoun "I." |
| antibiotic |
An antibiotic is a substance that can kill bacteria or prevent it from growing. Doctors use antibiotics to help patients who have infections caused by bacteria. Patients usually take antibiotics in the form of pills. |
| application |
An application is a request to do something, especially a request for a job, or a request to get into a college or other special school, or a request for permission for something. There is usually a form people have to fill out or other things they have to write or do in order to make their application. The form that people fill out is also called an "application." [1/3 definitions] |
| 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] |