Merriam-Webster has retooled its Word Central Website.
There are games, and a build your own dictionary feature.
If you have ever dealt with dictionaries, you know how important is to find the particular one you need. Working at my graduation paper, I had to work with different dictionaries on phraseology, and can recommend good source with many useful thematic dictionaries - http://www.ebook-search-queen.com/ebook/dict/dictionary.all.html
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