Complex sentence: In physics and thermodynamics, an equation of state is a thermodynamic equation relating state variables which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature (PVT), or internal energy.
Split into simpler sentences: In physics and thermodynamics, an equation of state is a thermodynamic equation relating state variables which describes the state of matter under a given set of physical conditions. It is a constitutive equation which provides a mathematical relationship between two or more state functions associated with the matter, such as its pressure, volume, temperature (PVT), or internal energy.