In this study, entropy definition and explanation in twelve general chemistry textbooks published in USA including what Korean universities select are analyzed. Analysis consists of two parts. One is diachronic analysis which focuses on the change between editions of same authors and the other is contents analysis composed of three sections? disorder in entropy definition and explanation, microstates number in entropy definition and explanation, possibility of alternative conception in learning statistical entropy and thermal entropy. As a result, the definition that entropy is the measure of disorder is denied and explanation using microstates number is introduced. Also, caution for the possibility of alternative conception that there are two different entropies is found. Reflecting the change in entropy explanation on new chemistry curriculum and reeducating teachers are meaningful on improvement of Korean chemistry education.