The Collaborative International Dictionary of English v.0.48:

Ba \Ba\ (b[aum]), v. t. [Cf. OF. baer to open the mouth, F.
   bayer.]
   To kiss. [Obs.] --Chaucer.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Ba
    n 1: a soft silvery metallic element of the alkali earth group;
         found in barite [syn: barium, Ba, atomic number 56]
    2: a bachelor's degree in arts and sciences [syn: Bachelor of
       Arts, BA, Artium Baccalaurens, AB]

The Free On-line Dictionary of Computing (19 January 2023):

ba

    The country code for Bosnia and Herzegowina.

   (1999-01-27)