The McGraw Hill Mathematics eGlossary provides written and verbal definitions and explanations of mathematics terms. The glossary is divided by grade level. Select your grade level then the first letter of the term for which you need an explanation. The explanation is offered in text form as well as verbal (click the speaker icon to listen). The eGlossary is also available in other languages including Spanish, Russian, and Chinese.
Wili the Word Wizard’s Math Dictionary is a glossary of important terms that elementary school and middle school students need to know to be successful in their mathematics classes. The dictionary includes diagrams when appropriate.
Jenny Eather’s A Maths Dictionary for Kids provides simple and clear definitions of math terms. Each definition includes a small diagram or simple activity to illustrate the term’s definition. A Maths Dictionary for Kids does not have a search option, but it doesn’t need one as all definitions appear alphabetically just like in a physical dictionary. Below you will see how the definition for least common denominator is explained.
Dictionary of Numbers is a neat Chrome extension that “translates” large numbers into terms that are easy to visualize. When you have the extension installed any time that you encounter a large number on the web you can highlight it and get a simple explanation of just how big that number is. For example, if you came across the number 238,900 you would quickly find out that that is the average distance in miles to the moon.
Harcourt School Publishers offers a nice little visual glossary of mathematics terms for elementary school students. The glossary is arranged by grade level and then alphabetically by term. Each term has a simple image and or animation. (The animations require Shockwave).