[General] I was an icident meeting.

[Tdol]

Which ones are better?
http://dictionary.cambridge.org/
http://dictionary.reference.com/
http://www.merriam-webster.com/
http://www.thefreedictionary.com/
http://www.oxforddictionaries.com/
http://www.ldoceonline.com/

Most are fine. I tend to use http://www.onelook.com/ and then click on individual dictionaries. I go for the ones published by standard publishers first, then look at the more specialised ones, depending on what I am searching for. It's hard to say whether Cambridge are better than Oxford or American Heritage, but if I am looking for slang then I will head for the Urban Dictionary. Try OneLook and see which results you like the most, but be prepared to use more than one; if one doesn't satisfy, try another.

 

[Tarheel]

My favorite is dictionary.com.

 

[MikeNewYork]

My favorite is "freedictionary.com".

 

[Matthew Wai]

My favorite is www.ldoceonline.com, which the above poster doesn't like.

Not a teacher.