Zeroeth Law 

A Zeroeth Law is a law that is added to another set of laws at a later date.

It is usually so important that the other laws cannot function without it, yet so obvious that nobody thought it needed stating.

The Zeroeth Law of thermodynamics: If objects B and C are both in thermal equilibrium with object A, then they are in thermal equilibrium with each other.

Isaac Asimov's Zeroth Law of Robotics: A robot may not harm humanity, or through inaction allow humanity to come to harm.

Newton's Zeroeth Law of Motion: If objects A and B are moving relative to object C at velocities v1 and v2, then they are moving relative to each other at velocity v3 which is the difference between v1 and v2. (Note: This law is now known not to be true, especially near the speed of light. That's where Einstein comes in)

The Zeroeth Commandment: Thou Shalt believe all of this and never question what thou art told.

Zeroeth Law by George McBob June 22, 2009

veselekov's zeroth law 

A scientific law explicitly stating that all members of the female race shall be unable to be sexually attracted to any man who has full autonomous control of their eyebrows. This does not hold true for any relationship that remains at a platonic level, such as friendships, or even jogging buddies. Predates his first law of gas, grass, or ass: no one rides for free

Player 1: Man, that dude's eyebrows are going everywhere! he's even doing the wave!

Player 2: He probably suffers from veselekov's zeroth law

veselekov's zeroth law by veselekov October 14, 2012