The Collaborative International Dictionary of English v.0.48:

Stern \Stern\, a.
   Being in the stern, or being astern; as, the stern davits.
   [1913 Webster]

   Stern board (Naut.), a going or falling astern; a loss of
      way in making a tack; as, to make a stern board. See
      Board, n., 8
   (b) .

   Stern chase. (Naut.)
   (a) See under Chase, n.
   (b) A stern chaser.

   Stern chaser (Naut.), a cannon placed in a ship's stern,
      pointing backward, and intended to annoy a ship that is in
      pursuit.

   Stern fast (Naut.), a rope used to confine the stern of a
      ship or other vessel, as to a wharf or buoy.

   Stern frame (Naut.), the framework of timber forms the
      stern of a ship.

   Stern knee. See Sternson.

   Stern port (Naut.), a port, or opening, in the stern of a
      ship.

   Stern sheets (Naut.), that part of an open boat which is
      between the stern and the aftmost seat of the rowers, --
      usually furnished with seats for passengers.

   Stern wheel, a paddle wheel attached to the stern of the
      steamboat which it propels.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chaser \Chas"er\, n.
   1. One who or that which chases; a pursuer; a driver; a
      hunter.
      [1913 Webster]

   2. (Naut.) Same as Chase gun, esp. in terms bow chaser
      and stern chaser. See under Bow, Stern.
      [1913 Webster]

WordNet (r) 3.0 (2006):

stern chaser
    n 1: a naval gun able to fire astern at a ship in chase