To grok ( /ˈɡrɒk/) is to intimately and completely share the same reality or line of thinking with another physical or conceptual entity. Author Robert A. Heinlein coined the term in his best-selling 1961 book Stranger in a Strange Land. In Heinlein's view, grokking is the intermingling of intelligence that necessarily affects both the observer and the observed. From the novel:
Grok means to understand so thoroughly that the observer becomes a part of the observedto merge, blend, intermarry, lose identity in group experience. It means almost everything that we mean by religion, philosophy, and scienceand it means as little to us (because of our Earthling assumptions) as color means to a blind man.