from The Century Dictionary.
- noun In submarine-cable work, a buoy anchored to mark any desired position or point.
Sorry, no etymologies found.
Doing little more than drift with the tide they crept past the submerged U-boat, one on either side of the mark-buoy that indicated her position.
With a splash a mark-buoy was dropped overboard to indicate the position of the shattered U-boat.
Orford Haven (that very difficult place) on the very top of an equinoctial springtide, picked up a racing mark-buoy, taking it to be moorings, and dragged it with him all the way to Aldborough, and that right before the town of Orford, so making himself hateful to the Orford people.
"But all this was way to one side of the mark-buoy, so fur as I was concerned.