I’ve often thought a reverse dictionary would be the ideal tool. If I already knew the word I wanted, why would I go look it up? What I know is the definition of the word I want. Thesauruses are great. You can usually find what you are looking for, but it still isn’t the same. I recently discovered OneLook and have been super pleased with the results. You can utilize it’s reverse dictionary feature to type in the definition of what you are looking for. In addition to that it has other neat word tools such as finding types of speech that start with a certain letter combination, expanding acronym phrases, and finding words that have certain meanings and are spelled in a particular fashion.
It has some fairly advanced features such as wild cards, which allow you to put a character in that will match any character for a search. They also can do phrase searches which include specific words. This can be really handy if you remember part of a phrase or you are looking for a phrase about a particular subject. For anyone trying to name something, write something, or just fascinated by words, it is a really handy tool.