[1] : 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
see also:
abbot 

[2] : 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."
   

[3] : Hitchcock's Bible Names Dictionary (late 1800's)

abba, father

Abba >> A Words
Abba, definition of term: Abba
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