Stands4.com is the biggest collection of acronyms and abbreviations that I have seen so far. It is, in fact, so big that the only way to find something is to use the search. Just to give you and idea – there are 10,100 entries just for the letter ‘T’!
There are few good things to note about this resource. Firstly, it provides acronyms and abbreviations from a range of categories – Computers, Business, Medicine, etc. Secondly, you can easily built a list of entries that you need often. It will be stored with your session and you don’t even have to register and/or login for this. Thirdly, there are international entries, such as in French or Latin for example. Many of these provide a translation into English. And fourthly, not only can your search for the meaning of the acronym or abbreviation, but you can do also a reverse search (in other words, find an acronym which meaning contains the word that your are looking for).