The Facts on File Dictionary of Mathematics, Fourth Edition contains more than 2,000 cross-referenced entries that explain, clearly and concisely, the most frequently used terms in mathematics. Revised and expanded since the previous edition published six years ago, this edition contains more than 300 new entries that articulate the advances made in mathematics. The most important new element in the dictionary is the inclusion of pronunciation symbols for more than 800 uncommon terms. The fourth edition features two new tools - a "Guide to Using the Dictionary" that explains the main features of dictionary entries and a "Pronunciation Key" that details how to interpret pronunciation symbols inserted next to an entry.
I have personally have used this book many times to define words in math. It has illustrations and clear, concise definitions of many of the terms students will encounter in any math class. The appendix has many formulas, conversion tables, and a list of math symbols with their meanings. It is a must to have for any student of math!