Languages

English Dictionary – vocabulary search:

Cambridge Dictionary Online
Collins English Dictionary
Dictionary.com is an Ask.com service. (Welsh included)
Merriam-Webster Online – Dictionary and Thesaurus
OneLook Dictioanry Search
Oxford Dictionaries
The Free Dictionary by Farlex
The Longman Dictionary of Contemporary English Online is an online version of the CD-ROM of the Longman Dictionary of Contemporary English, Updated Edition.
The Visual Thesaurus is an interactive dictionary and thesaurus that allows you to discover the connections between words in a visually captivating display.
Wiktionary is a free dictionary with English definitions from over 400 languages.
Wordnik is based on the principle that people learn words best by seeing them in context. They’ve collected more than 4 billion words of text (web pages, books, 0magazines, newspapers, etc.) and have mined them exhaustively to show you example sentences for any word you’re interested in.
WordReference.com is good for you to search the English words for the definitions in multiple languages.
YourDictionary has a comprehensive library of original articles. Get the answers you need on grammar, language, spelling, ESL, and more.
MetaGlossary is able to precisely extract the meanings of terms and phrases from the often frustratingly unmanageable mass of information on the web.