Dictionaries and resources for translation of mathematical terminology Nowadays English seems to be the most frequently used language in mathematics. (Although plenty of papers and books are published in other languages, e.g., Russian, French, German and Chinese.) 
However, mathematics is taught many other languages and there are occasions when we need a translation of some technical term, which is well-known in English, to other language.

  
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*Are there some dictionaries and other resources useful for translating from English to other languages?
  


There is somewhat similar question devoted specifically to Russian language: What resources are there for learning Russian math terminology?
One of the reasons I am asking this is this question which appeared recently at meta. In fact, the OP suggests in one part of this question creating some a kind of mathematical dictionary here at MSE.
 A: Some possibilities of finding the translations which I am aware of.


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*Wikipedia. Surprisingly, quite often, when I look at an article at English Wikipedia, I find translation of the term by checking language mutations of the article. Of course, this works better only for Wikipedias that are large enough.

*Wiktionary is a free online dictionary, which is built collaboratively. It seems that it contains some mathematical terminology, see e.g. Category:Mathematics or Category:Group theory.

*There exists the following book: Dictionary of mathematics, English-German-French-Russian, Berlin, VEB Verlag Technik, 1982. (Günther Eisenreich; Ralf Sube). This dictionary is organized into two parts; one with words, each word having some code. E.g. C1623, complexity, Komplexität, complexité, сложность. The second volume is a register in which you have (for each language) alphabetically ordered words with the codes, so that you can easily find them in the first volume. In this way it is relatively easy to add new languages (you only need to add the part with pairs between terms in this language and the code used in the book). I don't know whether such additions were published in other languages, too, but I happen to have this dictionary where Slovak language is added: Matematika: anglicko-nemecko-francúzsko-rusko-slovenský slovník. Bratislava : Alfa ; Berlin : VEB Verlag Technik, 1982. When I find a mathematical term in this dictionary, I consider the Slovak translation from this dictionary as a standard. Here are examples what the pages in this dictionary look like: A, B

*Math dictionary at http://mathdict.chitanka.info/en/de-en/ - this online dictionary has 3 languages: Bulgarian, German and English. I've learned about it from an answer to this question.

*There also exists this English-Russian, Russian-English dictionary: Александров П.С.: Англо-русский словарь математических терминов 2 изд. Мир, 1994. Another Russian-English mathematical dictionary was mentioned in 042's answer.
A: For Russian-English dictionary, try Lohwater: Russian-English Dictionary of the Mathematical Sciences. 
Moreover, in some cases, checking interwiki links at Wikipedia can be also helpful.
A: For German to English and vice versa: see Hyman's German-English Mathematics Dictionary. It is slightly dated, but good enough for translating that one result you can only find in a German paper from the 1950s. 
A: There is a 6-page English–Swedish–Esperanto–French–German (!) mathematical dictionary (somewhat geared towards PDEs) compiled by Christer Kiselman:
http://www.math.uu.se/~kiselman/wordpde.pdf
A: The math department of Princeton has a list of German words online, seemingly for people who want to read German math papers.  The umlauts are missing, though... :)
A: For English, German, French To Arabic and vice versa, consult BASM http://basm.kacst.edu.sa/

However arabic terms is somehow obscure even for arabs, every country make different translation.
A: For Spanish (Castellano) ⇔ English:


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*Bilingual mathematics dictionary by Norman Koch

*Diccionario de matemáticas : castellano-inglés, inglés-castellano = Dictionary of mathematics : English-Spanish, Spanish-English by Kenneth Allen Hornak


French ⇔ English
English-French-German-Spanish:


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*Dictionary of science and technology in English-French-German-Spanish, containing 10,000 current terms in the English language most frequently used in the physical sciences and their applied fields, together with separated indices in French, German, and Spanish, conversion tables, and technical abbreviations. (1943) by Maxim Newmark

A: I have found this online French-English/English-French dictionary of mathematical terms useful:
Lexique Français-Anglais
An interesting resource for English speakers seeking to read French papers, and which goes beyond a simple lexicon, is
French For Mathematicians: A linguistic approach 
by Joël Bellache at Brandeis. 
