Abba

from The Collaborative International Dictionary of English v.0.48

Abba \Ab"ba\ ([a^]b"b[.a]), n. [Syriac abb[=a] father. See
   {Abbot}.]
   Father; religious superior; -- in the Syriac, Coptic, and
   Ethiopic churches, a title given to the bishops, and by the
   bishops to the patriarch.
   [1913 Webster]

from Easton's 1897 Bible Dictionary

Abba
This Syriac or Chaldee word is found three times in the New
Testament (Mark 14:36; Rom. 8:15; Gal. 4:6), and in each case is
followed by its Greek equivalent, which is translated "father."
It is a term expressing warm affection and filial confidence. It
has no perfect equivalent in our language. It has passed into
European languages as an ecclesiastical term, "abbot."

from Hitchcock's Bible Names Dictionary (late 1800's)

Abba, father

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