1. The Online Slang Dictionary: A slang dictionary clearly restricts itself to a certain feature of a language, in this case: slang!

2. Collins English Dictionary: The CED is a monolingual general dictionary which deals which focuses on the general standard language in use.

3. Roget` s Thesaurus: Roget` s thesaurus is restricted because it only focuses on one aspect of the language: synonymy.

4. Oxford English Dictionary: see also: CED