TBESG
Ἀββά (T, -ᾶ), indecl. (Aram, אַבָּא, emphatic form of אַב = Heb. אָב, father),
used in the phrase Ἀ. ὁ παήρ, Abba, Father (see Swete on Mk, I.with): Mrk.14:36, Rom.8:15, Gal.4:6.†
(AS)
Translators Brief lexicon of Extended Strongs for Greek based on Abbot-Smith, A Manual Greek Lexicon of the New Testament (1922) (=AS), with corrections and adapted by Tyndale Scholars