Creating an central multi-purpose dictionary / database I am trying to organize my workflow and make it more effective. 

As non-native English-speaker studying in a foreign country I often need to look-up domain-specific translations (in 3 languages). As there are no specific dictionaries I am using textfiles containing translations I have collected over the time. 
This is quite uncomfortable.

Often these words are related to some kind of mathematical definition which has to be stated as a theorem for proofs. Right now I usually copy these from my old publications.

It would be great to have some kind of central dictionary or knowledge-base where I could organize all this (Translations and Definitions).  


Anyone who can recommend a program for this?
How do you organize definitions and domain-specific translations?
I would try http://termbases.eu/ a site that was mentioned under Software: Lexicons in Linguist List.

Broadly, what you have described is a lightweight variety of a dictionary writing system, software for developing a lexicon.

If you were translating digital documents, I would recommend translation memory software. Collecting and managing your multilingual context-specific translations is part of what translation memory software does.

Another possibility, if you happen to be comfortable setting up a wiki, is to create a wiki in the manner of Wiktionary.