The story
Blend of en[ergy] + trans[fer] + [abilit]y, introduced on 26 February 2007 by a research group at Tsinghua University led by Professor Guo as a basis for optimizing heat transfer processes (Guo, Zeng-Yuan; Zhu, Hong-Ye; Liang, Xin-Gang. Entransy—a physical quantity describing heat transfer ability International Journal of Heat and Mass Transfer, no. 50, pp. 2545–56, available online 26 February 2007). A descriptive concept of entransy, but without using the term ‘entransy’, was first proposed by Professor Guo's group in February 2003 as ‘heat transport potential capacity’.
Etymology from Wiktionary, CC BY-SA 4.0.