grok definition by American Heritage Dictionary
transitive verb grok·ked, grok·king, groks Slang
Origin: Coined by Robert A. Heinlein in his Stranger in a Strange Land.
grok - Computer Definition
To have a thorough understanding of a subject. The word comes from Robert Heinlein's "Stranger in a Strange Land," and it means "to drink" in Martian. Of course. But more specifically in the book, it meant to take something in so thoroughly that it becomes part of you.