Secret society

Ben had much fun out of it, assuring the other boys that those were the signs and password of a secret society to which he and Sam belonged.

But these Brothers of Pity were a secret society, known to no man except their spiritual head, who chose them in turn, and not knowing even each other.

Originally a secret society, B'nai B'rith came into the open in 1920 with publication of its ritual.

In the opening scenes of "The Good Shepherd," the hero (played by Matt Damon) is initiated into Skull and Bones, Yale's iconic secret society, by lowering himself naked into a coffin to confess his deepest secrets.

[…] obedience and loyalty were also 'important bywords' to the Ghee Hin, Ghee Hok and Ho Seng secret societies […]