OK. Entity extraction for a specific series of entities types can certainly be done (one could write a chatscript script to do it). However, they are almost always assuming the case of the incoming text is correct, which in chat is rarely true. And extracting an entity is not the same as deciding which meaning of orange to use given incoming text. I had thought you were seeking generalized resolution of which meaning of a word was being used, which is a much more complex problem than finding geographic names in some text.