Abaft

Abaft \A*baft"\ ([.a]*b[.a]ft"), prep. [Pref. a- on + OE. baft,
   baften, biaften, AS. be[ae]ftan; be by + [ae]ftan behind. See
   After, Aft, By.] (Naut.)
   Behind; toward the stern from; as, abaft the wheelhouse.
   [1913 Webster]

   Abaft the beam. See under Beam.
      [1913 Webster]See also:
After Aft By Abaft the beam Beam 

Abaft \A*baft"\, adv. (Naut.)
   Toward the stern; aft; as, to go abaft.
   [1913 Webster]