Source : Webster's Revised Unabridged Dictionary (1913)

Dockage \Dock"age\, n.
   A charge for the use of a dock.

Source : WordNet®

dockage
     n 1: a fee charged for a vessel to use a dock [syn: {docking fee}]
     2: landing in a harbor next to a pier where ships are loaded
        and unloaded or repaired; may have gates to let water in
        or out; "the ship arrived at the dock more than a day
        late" [syn: {dock}, {docking facility}]