Gess has a true thirst for knowledge. I know this because she is constantly asking about things she does not understand. If we say a word and she doesn't know what it is she immediately responds with "what's that mean?" Gess is also a very visual learner so explaining things to her using graphics is extremely helpful as well so when I found this cool FREE resource I had to bookmark it.
Here is a link to the Visual Mathematics Dictionary which, as its name implies uses visual references for many of the definitions. You can sort the lists by K-2, 3-5, 6-8 or K-12. Here is one example of how the definition will read. I do wish the font was larger so it was easier for Gess to read the answer but she can certainly see how it works.
If you need a little help with math vocabulary you might want to keep the Visual Mathematics Dictionary handy.