The title of this song was long rumored to be an acronym for Nativity in Black, a reference to the birth of the antichrist. The lyrics are also from the point of view of Lucifer, who identifies himself. The rumors turned out to be wrong, however.

Butler later referred to it as

just a humorous take on Satan falling in love.

Ozzy and Iommi also stated that

the title has nothing to do with the content of the song.

The famous bass solo by Geezer Butler at the beginning of the song is named “Bassically.”