order of phase transition

order of phase transition

[′ȯrd·ər əv ′fāz tran‚zish·ən] (thermodynamics) A phase transition in which there is a latent heat and an abrupt change in properties, such as in density, is a first-order transition; if there is not such a change, the order of the transition is one greater than the lowest derivative of such properties with respect to temperature which has a discontinuity.