Dictionary word, as the name suggests, is a word found in the dictionary.
Not ALL dictionary words are valuable.
The dictionary word must be a common one, and should appeal to a particular niche which is monetarily profitable. If the dictionary word in question is like money, cash, grow, pen, car, house, jeeps (heh) etc, then you can easily monetize it OR sell it to a end user looking to start / evolve business in that particular niche. For him, this name would be invaluable, as it would pull type in traffic and would also be memorable to the user.
If the name is something like trodden, drained, thoughtful, sneering etc, you can easily see these names wouldnt be in demand with any business or niche who could monetize the same or launch their businesses on it.
So, all in all, not all dictionary names are valuable, only the ones you or somebody else can earn money from.
HTH,
Kross.