The Five in One Dictionary

Dictionary.com is a 5 in 1 dictionary which has many uses -

1. Dictionary
2. Thesaurus
3. Encyclopedia
4. All Reference
5. The Web

Dictionary

 As its name is, dictionary.com has a dictionary which can give you the meaning of any English word and if spelt wrong can give you different options and words to select from.

Thesaurus

Dictionary.com also has its own Thesaurus, so if you don't seem to have a local library or you can't go to the library and you have internet, than dictionary.com is the way to go.

Encyclopedia

My favorite, the encyclopedia has many, many interesting things to look at and read, you might also need to use the encyclopedia a lot to find out stuff or just look at the awesome things. Again, can't go to the library; well here is your online encyclopedia.

All Reference

You might as well use this for all your searches, but all you get is more answers and more information, it gives you all the information that can be found on the web and in encyclopedias etc.

The Web

Just like Google  and Yahoo, Dictionary.com gathers information from the web to answer you.