Thermodynamics characterizes a state of equilibrium by properties such as volume, pressure, temperature, composition.
Thermodynamic properties can be classified as intensive and extensive . Those that do not depend on the amount of matter in the system (pressure, temperature, composition) are intensive. The extensive ones depend on the size of the system (mass, volume).
When a thermodynamic system is in a certain state of equilibrium, each thermodynamic variable will take on a specific value characteristic of that state of equilibrium. If we make the system evolve towards another state of equilibrium, the thermodynamic variables will be modified. Thermodynamic variables are also called state functions, since their value depends only on the equilibrium state and not on the path followed to reach it. For example, the thermodynamic variables of a system formed by water at 25ºC are the same whether you prepare it by melting ice or condensing water vapor.