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.
Military doctrine is the expression of how military forces contribute to campaigns, major operations, battles, and engagements. It is a guide to action, rather than hard and fast rules. Doctrine provides a common frame of reference across the military.