I have a geek confession. I always thought grok just came from Unix. Oh no, I’m a dork, not a geek! How embarrassing….
The word “grok” comes from Robert A. Heinlein’s Zen-hippie science fiction opus Stranger in a Strange Land. It’s a verb from the Martian language that means something along the lines of “to understand completely.” To grok something is to achieve a deep, intuitive comprehension of it. – How to Grok Web Standards by Craig Cook on A List Apart