Source : Free On-Line Dictionary of Computing

grok
     
        /grok/, /grohk/ (From the novel "Stranger in a Strange Land",
        by Robert A. Heinlein, where it is a Martian word meaning
        literally "to drink" and metaphorically "to be one with")
     
        1. To understand, usually in a global sense.  Connotes
        intimate and exhaustive knowledge.
     
        Contrast {zen}, which is similar supernal understanding
        experienced as a single brief flash.  See also {glark}.
     
        2. Used of programs, may connote merely sufficient
        understanding.  "Almost all C compilers grok the "void" type
        these days."
     
        [{Jargon File}]
     
        (1995-01-31)