This is the smaller mast located just behind the main mast of a ship.
the hindmost mast of a three-masted vessel.
the mast at the stern or back of a vessel; in a 3 masted ship the mast at the front is the foremast, the mast in the middle is the mainmast, the mast at the stern is the mizzenmast.
the aftermast on a yawl or ketch.
(or Mizzen) - The third mast of a ship.
the third mast aft on sailing ships carrying three or more masts
Aboard the three-masted Concordia, the aft most of the three(empty)(empty)
The mast abaft the mainmast. The third mast from the bow on a ship of three or more masts. (See rigging illustration.)