Mathematics

Bidirectional English-Czech Mathematics Dictionary
Translates mathematical terminology in the language pair English-Czech.
http://www.umat.feec.vutbr.cz/%7enovakm/slovnik_matematicke_terminologie/index_en.html

Big Number Names
List of words used for powers of ten. For instance, novemtrigintillion=10^120. Also has metric prefixes, metric numeric symbols, and corresponding European equivalents.
http://g42.org/MiscInfo/numbers.html

Common Terms in Mathematics
A glossary compiled by Dilara and M.Tevfik Dorak.
http://dorakmt.tripod.com/mtd/glosmath.html

The Computational Beauty of Nature
Concise definitions, cross referenced, for the areas of computation that examine complex systems, fractals, chaos and adaptation.
http://mitpress.mit.edu/books/FLAOH/cbnhtml/glossary.html

Dictionary of Algorithms and Data Structures
Definitions of terms related to algorithms, algorithmic techniques, data structures and archetypal problems.
http://www.nist.gov/dads/

Dictionary of Number Words
A dictionary of English words, phrases, prefixes, suffixes, and symbols that describe numbers.
http://home.comcast.net/~igpl/Number_Words.html

Glossary of Mathematical Mistakes
Cross-referenced list of common mathematical mistakes made by people in a variety of contexts.
http://members.cox.net/mathmistakes/

Glossary Of Statistical Terms
Compiled by M. Tevfik Dorak.
http://dorakmt.tripod.com/mtd/glosstat.html

The Internet Glossary of Statistical Terms
Glossary of terms organized according to learning order for those unfamiliar with the subject, and also an alphabetical list for already familiar with statistical procedure.
http://www.animatedsoftware.com/statglos/statglos.htm

K-12 Math Dictionary
K-12 math terms and definitions with illustrations.
http://www.mathematicsdictionary.com

Mathematical Latin Terms and Phrases
Latin terms commonly used in mathematics and a more list of such terms and phrases that occur in other contexts.
http://www.mathacademy.com/pr/prime/articles/latin/

Mathematical Programming Glossary
Contains terms specific to mathematical programming and related disciplines like economics and computer science.
http://glossary.computing.society.informs.org/

MathVoc
Translation of mathematical vocabulary between English, French and Spanish.
http://membres.lycos.fr/mathvoc/

OECD Glossary of Statistical Terms
Comprehensive source of definitions relating statistical concepts, variables and acronyms.
http://stats.oecd.org/glossary/index.htm

Wolfram MathWorld Alphabetical Listing
Definitions of the entries covering all relevant fields of mathematics.
http://mathworld.wolfram.com/letters/