When you create a group, you can choose 3 privacy settings: Public, Closed and Secret. The table below shows who can join these groups and what people can see about them. If you're an admin of a group, learn how to change the privacy settings of your group.
For the album by Pestilence, see Doctrine (album). Doctrine (from Latin: doctrina) is a codification of beliefs or a body of teachings or instructions, taught principles or positions, as the essence of teachings in a given branch of knowledge or belief system. The Greek analogue is the etymology of catechism.
Latin root word is religio the bind, or to tie up that is the meaning. Jesus said that true religion is caring for widows and orphans. This leads me to believe the original meaning has more to do with what you do rather than what you believe.