I use Merriam-Webster and Wiktionary. I'm looking for a way to search within definitions and do other searches on either of those sites or a site where these kinds of searches can be performed.
- search for all words that contain a word or phrase in their definition
- search for all words that match a pattern: eg.
- not essential: search on parts of speech or etymology
- Boolean combinations
I once had some desktop software that would do this. I know the patterns can be searched in scrabble dictionaries, but they don't often have full-text definitions.