I have a project where we’re using Formatted Text Control as a word processor and our Spell Checking Plugin that does cross-platform spell checking (either from the OS or Hunspell dictionaries). The client is wondering if we can add Thesaurus capabilities and so far I’m not finding anything.

At one point I thought there was a thesaurus built into Mac OS X but I’m not finding it in Sierra. Did this go away? Is there anything built-in to Windows?

And if we eliminate built-in options are there any options for 3rd party or open-source libraries?

It’s part of the dictionary app now.

What about Windows?

Honestly I haven’t looked.