Rules

Rule 34 is an Internet meme which claims that some form of pornography exists concerning every possible topic. The concept is commonly depicted as fan art of normally non-erotic subjects engaging in sexual activity. It can also include writings, animations, images, GIFs and any other form of media to which the Internet provides opportunities for proliferation and redistribution.

set of three rules proposed by physicist Friedrich Hund

Used to determine direction of the coil

set of rules outlining the responsibilities of, or proper practices for, an individual, party or organization

Rules for elements dissolving in a solid metal

rules that are not written down

rule dealing with the filling of electrons into orbitals belonging to same shell

legal strategy used by authors to evade libel lawsuits

obedience to a military code of conduct

Internet meme involving gender reversal of an existing male/female character

A guideline is a statement by which to determine a course of action. It aims to streamline particular processes according to a set routine or sound practice. They may be issued by and used by any organization (governmental or private) to make the actions of its employees or divisions more predictable, and presumably of higher quality. A guideline is similar to a rule, but are legally less binding as justified deviations are possible.

Cold War era safety precautions, used by spies

refusal of some journals to publish non-new material

social group or culture's informal norms that distinguish how one should express themselves

Guideline governing legal pleas of insanity

rule for describing which strings of symbols formed from the alphabet of a formal language are syntactically valid within the language