Use this free, interactive tutorial to improve your Internet research skills: Tour the best of the web for mathematics. Discover how to search the internet effectively. Judge which websites are worth using....
An animated, interactive dictionary for students which explains over 600 common mathematical terms in simple language."
"ANIMATED - definitions, examples, activities, practice, calculators - INTERACTIVE
The NSDL was created by the National Science Foundation in 2000 to provide organized access to high quality online resources and tools that support innovations in teaching and learning at all levels of science, technology, engineering, and mathematics education.
As you read through various definitions for dictionary most of the definitions include the word book as part of the definition. Yet, there is not question that online dictionaries abound. My preferred definition of dictionary as it relates to this post is…"a book [resource] giving information on particular subjects or on a particular class of words, names, or facts, usually arranged alphabetically: a biographical dictionary; a dictionary of mathematics."
Today's Wolfram|Alpha is the first step in an ambitious, long-term project to make all systematic knowledge immediately computable by anyone. You enter your question or calculation, and Wolfram|Alpha uses its built-in algorithms and growing collection of data to compute the answer.