Late 19th century; earliest use found in John S. Billings (1838–1913). From mass or mass- + -o- + therapy, after e.g. hydrotherapy, electrotherapy, etc.
英语词典包含243303条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。