I found this website just the other day and was very impressed with the quality of results I was able to get. It is an nice aggregated dictionary search of many online dictionaries. I like the fact that it will give you a quick general definition and then let you seek out as many follow up definitions as you like.

However the thing I liked most about this site was the reverse lookup. It gave me some good results without much hassle. I truly found what I wanted by only having to take ‘one look’.

http://www.onelook.com