I'm looking for something like Google Sets, but in API form. Google Sets doesn't allow scraping, nor does it have an API.
Example, I'd like to search for "electronics" and have it return "cd player, television, telephone, computer, etc...". Possibly, like Google Sets, have it take a couple words.
A good example of the results I'm looking for is the site GoRank's search tool. I could scrape that, but I'd rather not... Any ideas?
Take a look at the Big Huge Thesaurus API:
http://words.bighugelabs.com/api.php
http://blog.programmableweb.com/2008/09/04/big-huge-thesaurus-api-access-145000-words-and-phrases/
Hopefully this will work.... You can also check out WordNet, but if you want an web service you'll have to host your own (but there's code for it!): http://wnws.sourceforge.net/
Sounds like what you are looking for is not a thesaurus as you are not looking for alternate words with similar meanings but you are actually looking for words that all have some tangential relationships.
Haven't tried this myself but this might be a good place to start
http://www.wait-till-i.com/2008/11/13/yahoo-boss-keyword-extraction-api-wrappers-jsphp/
May be that wordnet can help you: http://wordnet.princeton.edu/
In face wordnet is a large lexical database of English, here words are interlinked by means of conceptual-semantic and lexical relations.