Question

why is zeroth law known as zeroth in thermodynamics not in natural number ???

Answer 1

because it was proposed later and was a very basic law..

Answer 2

as it is the basic principle which explain the direction of flow of heat .....and it was introduced after first and second law............so scientist can't change the order by arrange zeroth law to the first ;law because at that time first law was very famous so they decided it to name as zeroth law