Board Thread:Versus Debates/@comment-32466165-20170722022140/@comment-25122992-20170803190839

Susanoo has always ended up in the jutsu section within the databook, and it was classified there as such (ninjutsu and kekkei genkai). Also, Itachi called it a technique that was awakened along with his other MS jutsu, Amaterasu and Tsukuyomi. So your assumption about Susanoo as a "living being" is highly farfetched and isn't actually true. Plus, you must realise that the literal translation of the name doesn't really matter, since Susanoo name comes from an actual name of a Japanese deity.

Edit: I checked the databooks, they actually say that Susanoo is formed from the user's chakra = it's still a chakra avatar. Checkmate.