[ghaff]

It's a really great word. We don't really have an equivalent in English that doesn't require some long awkward phraseology. "Deeply understand something at a fundamental level."

[lazyant]

"get" is pretty close imho

[TchoBeer]

I can think of several words like that, "comprehend" is the first one that springs to mind.

[wumpus]

Have you actually read the book to observe how it was used there, or are you just responding to the previous comment?

[miles]

"Comprehend" is a weak, distant cousin of "grok":

grok: "understand (something) intuitively or by empathy; [no object] empathize or communicate sympathetically, establish a rapport"

comprehend: "grasp mentally; understand"

[handrous]

To be fair, in real life, I usually see it used as a straight synonym for "understand" or "comprehend", just with extra geekiness. Very rarely is its special meaning actually intended.

[prepend]

I’ve never seen it used in that way, almost always it means to completely know something on a very deep level. To know it inside and out, etc.

[xref]

Much more common is “expert” or “mastery” for that level of understanding, when I hear “grok” it means they read the Wikipedia page or did the tutorial or something.