Σαβαὼθ, Sabaoth is the Greek transcription of צְבָאוֹת, plural of צָבָא=army, in a name applied to God κύριος Σ.=יהוָה צְבָאוֹת Yahweh Lord of the Armies, Lord of Hosts.1
Paul uses this word in Romans:
καὶ καθὼς προείρηκεν Ἠσαΐας εἰ μὴ κύριος Σαβαὼθ ἐγκατέλιπεν ἡμῖν σπέρμα ὡς Σόδομα ἂν ἐγενήθημεν καὶ ὡς Γόμορρα ἂν ὡμοιώθημεν (GNT and TR)
And as Isaiah said before: “Unless the Lord of Sabaoth had left us a seed, We would have become like Sodom, And we would have been made like Gomorrah." (Romans 9:29 NKJV)
The NWT looks past the actual Greek to render the word based on the Hebrew meaning:
Also, just as Isaiah had said aforetime: "Unless Jehovah of armies had left a seed to us, we should have become just like Sodom and we should have been made just like Gomorrah." (NWT)
Is this a reasonable translation?
1. Fredrick William Danker, A Greek-English Lexicon of the New Testament and Other Early Christian Literature, The University Chicago Press, 2000, p. 909