Ἀββᾶ
From LSJ
Τὸ νικᾶν αὐτὸν αὑτὸν πασῶν νικῶν πρώτη τε καὶ ἀρίστη. Τὸ δὲ ἡττᾶσθαι αὐτὸν ὑφ' ἑαυτοῦ πάντων αἴσχιστόν τε ἅμα καὶ κάκιστον. → Τo conquer yourself is the first and best victory of all, while to be conquered by yourself is of all the most shameful as well as evil
English (Strong)
of Chaldee origin (אַב); father as a vocative: Abba.
English (Thayer)
(WH (βά), Hebrew אָב father, in the Chaldean emphatic state, אַבָּא i. e. ὁ πατήρ, a customary title of God in prayer. Whenever it occurs in the N. T. (אַבָּא, through frequent use in prayer, gradually acquired the nature of a most sacred proper name, to which the Greek-speaking Jews added the appellative from their own tongue.
Greek Monotonic
Ἀββᾶ: Εβρ. λέξη, πατέρας, σε Καινή Διαθήκη