Tricameralism is the practice of having three legislative or parliamentary chambers. It is contrasted to unicameralism and bicameralism, both of which are far more common.
tricameralism:
tricameral +? -ism.
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。