"det ord" is wrong, you need to write "det ordet", but that wouldn't be the right way to say it.
Either "Hva betyr 'boken'?" or "Hva betyr ordet 'boken'?" or just "Hva betyr det (ordet)?".
The first one would be uncommon in this case, as everyone would know what 'boken' means, but you could phrase it like that if the word was more complicated or uncommon, like 'diminutiv' or 'cicero'.
The second one would be a bit formal, and could be from a quiz asking the meaning of the word.
The third one would be used as in the first example, because it would be obvious what you meant if the speaker used a complicated/uncommon word. If you were reading a book and was to ask someone what a word mean, you might add "ordet" while pointing to the book.
A fourth way of saying it, would be "bok-hva-for-noe?" where you would repeat the first part of the word and say 'hva-for-noe'. This would strictly be for colloquial use, so I don't suggest you use it.
I would suggest using the second if you're still learning new words, as it would probably be the clearest and easiest to understand, as the others would most likely be used for more difficult words.