I want to go through the case of a solid-solid equilibrium.

固相固相平衡。

youdao

The point at which the solid and the liquid are in equilibrium is called the freezing point.

固体和液体的平衡点叫做冰点。

《牛津词典》

But again, if you know all the energies of the possible states, in the solid, in the liquid and the gas, statistical mechanics shows us that we can calculate the equilibrium between those.

但是，如果我们知道，物质在固相，液相和气相中所有可能态的能量，统计力学告诉我们，我们可以计算这些相的平衡问题。

youdao

So the triple point is liquid solid, gas, all in equilibrium.

气态，固态，三相平衡,你可能会想。

麻省理工公开课 - 热力学与动力学课程节选

and added a structure of math upon it, to build this edifice, which is a very solid edifice of thermodynamics as a science of equilibrium systems.

了这座热力学的坚固大厦，这是一门，平衡态系统,的科学。

麻省理工公开课 - 热力学与动力学课程节选

And the triple point of water is 16K that temperature and pressure - there's a unique temperature and pressure where water exists in equilibrium between the liquid phase, the vapor phase, and the solid phase.

与水的三相点,我们定义它为273。,水的三相点,是一个特定的温度和压强,可以使水的液态，气态和固态三相共同达到平衡，三相点是液态。

麻省理工公开课 - 热力学与动力学课程节选