For those interested, I also developed Describing Words which helps you find adjectives and interesting descriptors for things (e.g. So this project, Reverse Dictionary, is meant to go hand-in-hand with Related Words to act as a word-finding and brainstorming toolset.

That project is closer to a thesaurus in the sense that it returns synonyms for a word (or short phrase) query, but it also returns many broadly related words that aren't included in thesauri. I made this tool after working on Related Words which is a very similar tool, except it uses a bunch of algorithms and multiple databases to find similar words to a search query. So in a sense, this tool is a 'search engine for words', or a sentence to word converter. It acts a lot like a thesaurus except that it allows you to search with a definition, rather than a single word. The engine has indexed several million definitions so far, and at this stage it's starting to give consistently good results (though it may return weird results sometimes).

For example, if you type something like 'longing for a time in the past', then the engine will return 'nostalgia'. It simply looks through tonnes of dictionary definitions and grabs the ones that most closely match your search query. The way Reverse Dictionary works is pretty simple.

Road to nowhere meaning