Acronym Finder
"With more than 1,000,000 human-edited definitions, Acronym Finder is the world's largest and most comprehensive dictionary of acronyms, abbreviations, and initialisms."

The Alternative Dictionaries
"The Alternative Dictionaries (TAD) are a collection of «bad» words and expression from all over the world. Contributions are made by internet users."

Digital Dictionaries of South Asia

Latin Dictionary and Grammar Aid

Logosdictionary
"The Dictionary features 251 languages and is committed to preserve languages in danger of extinction, by allocating the same prominence to each language irrespective of the number of people who speak it or of the political/economic weight of the country in which it is spoken."