There are four laws of thermodynamics, zeroth to third:Zeroth law. If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each...
The zeroth law of thermodynamics recognizes that if two systems are in thermal equilibrium with a third, they are also in thermal equilibrium with each other, thus supporting the notions of...
There are actually 3 Laws of Thermodynamics (the actual number is debatable, but the number ranges from 3-5, depending on your adding skills). See the link below, wikipedia does an adequate job of...