Grok (pronounced GROCK) is a verb from Robert A. Heinlein's science fiction novel, Stranger in a Strange Land (1961). In it, a Martian visits earth and brings his language from Mars. Grok means to understand, in an utterly complete and intuitive way. It's the Martian equivalent of to "get it", and the youth culture adopted this new word into the English language. The word is included in the American Heritage  and Merriam-Webster dictionaries. It is sometimes associated with hippies and computer programmers
In Heinlein's novel, a character asks another to explain the word: "You speak Martian... Do you grok 'grok?'" The other replies:
- "No. 'Grok' is the most important word in the language—and I expect to spend years trying to understand it. But I don't expect to be successful.... Its literal meaning... is easy. 'Grok' means 'to drink....' 'Grok' means to understand so thoroughly that the observer becomes a part of the observed—to merge, blend, intermarry, lose identity in group experience.... Jubal, if I chopped you up and made a stew, you and the stew, whatever was in it, would grok—and when I ate you, we would grok together and nothing would be lost and it would not matter which one of us did the eating."
- "It would to me!" Jubal said firmly.
The emphatic form is to grok in fullness.
Examples of usage:
- A cult gives its members license to feel superior to the rest of the universe, and so does a cult movie: it confers hipness on those who grok what the mainstream audience can't.
- After all, therapists not only grok, but they have to grok fellow human beings who are anguished, defeated, and often at their wit's end, or, certainly, not at their best.
Grok is perhaps the only English word that comes from the fictional language of Mars.
- McCleary, John Bassett, The Hippie Dictionary: A Cultural Encyclopedia (And Phraseicon) of the 1960s and 1970s,p. 223
- The Hacker's Dictionary
- Heinlein, Robert (1961), Stranger in a Strange Land, chapter XXL. p. 205-6 of the Berkley Medallion paperback edition, SBN 425-01756-7. Note: this is a very abbreviated extract from a much longer and more complicated presentation.
- Edelstein, David (2004), "You're Entering a World of Lebowski, The New York Times, August 8, 2004, p. 21
- Brady, Mark, The Wisdom of Listening, p. 94