My nan has this reverse dictionary, but I never saw how it works. Aparantly, if you know the meaning of a word but can't remember what it is, you can some how look it up and it tells you the word, but how?
I've used a reverse dictionary for years - very good for obscure words needed for crosswords. Say you needed the word for 'shaped like a sword', you look up sword and it will have subheads like 'shaped like a s', 's with curved blade' etc.