Wordnik.com

Wordnik is a simple and easy to understand dictionary. The website has a very plain view but is split up into several sections to make it easy to find the part you learn from best.  For example, if you are a visual learner you could use the pictures to try to make sense of the word you are looking for.  Although some of the pictures are only loosely related to the original word so if young children are using this you would need to ensure they understood this.  

If you are an audio learner you can use the audio link to understand how the word should be pronounced and if you simply learn from explanations then there are several sections that go into great detail to help gain a full explanation.  One of these sections is definition which you would expect to see in any dictionary.  The information is taken from many different sources so  if you don't understand one explanation then you may see it better from another source.  The fact it does not allow user definitions is a good thing, as this means all information has to be verified first before it is added to the website. There is a section on the page you can use to add your comments and have a discussion about the word but this is separate and should be used with care.

The next very useful section is examples.  This lets you see the word in a sentence, showing it in as many different ways as possible, helping you to put the word into context to understand the meaning.  It shows you words it is related to and helps you to see the bigger picture.

This would all be useful in an educational setting as the different learning style approaches makes it fun to use.  The majority of children enjoy using technology to learn and why should English be any different.  A particularly fun part of the site is the word of the day or random word tabs.  You could use this in lessons to try to expand yours or a child's vocabulary so that you are learning together.  Adding this into the beginning of the day, you could try to encourage children to use the word in a sentence during the day.  Looking at the site now, the word of the day is "Chasse" and the random word is "Snood", instead of telling you what they mean though I will let you try the website out for yourself www.wordnik.com.