OneLook Dictionary Search
More than 13 years old , with a database of 5 million words..no doubt onelookdictionary is indexed by more than 1024 online dictionaries.You can find, define and translate words all at this site.A must for every word lovers!
Visuwords
Look up for words to find their meanings and its associations with other words and concepts. Make diagrams reminiscent of a neural net. Learn how words are associated.
Merriam Webster: Visual Dictionary
The Visual Dictionary Online is an interactive dictionary with an innovative approach. From the image to the word and its definition, the Visual Dictionary Online is an all-in-one reference. Search the themes to quickly locate words, or find the meaning of a word by viewing the image it represents. What’s more, the Visual Dictionary Online helps you learn English in a visual and accessible way.
OneLook’s reverse dictionary lets you describe a concept and get back a list of words and phrases related to that concept. Your description can be a few words, a sentence, a question, or even just a single word.
Online Spell Checker
Free online spell checker that provides you with quick and accurate results for texts in 28 languages (German, English, Spanish, French, Russian, Italian, Portuguese etc.). An alternative tool: Spelljax.
WordWeb
A one-click English thesaurus and dictionary for Windows that can look up words in almost any program. It works off-line, but can also look up words in web references such as the Wikipedia encyclopedia. Features of the free version include definitions and synonyms, proper nouns, 150 000 root words and 120 000 synonym sets.