Google Dorking can technically be defined as a type of hacking by itself. The basic idea of Google Dorking is to used Google’s advanced search features/operators to obtain information about someone, or something.
In general we know that Google Search is a big database of all the webpages that are considered publicly searchable (I’m not going into deep web in this article). Public webpages are websites that googles spider has access to. It is possible to make your website not searchable by telling Google’s search spider that you do not wish for it to crawl and index your website. That being said I think you’ll find that most websites on the internet are intended to be found and as such can be searched using dorks.