a level or part within a system or set of ideas 层次；阶层◆There were too many layers of management in the company. 这家公司的管理层有太多层级。
a quantity or thickness of sth that lies over a surface or between surfaces 层；表层◆Finally, three layers of protective coating are sprayed onto the wood. 最後，在木材上喷上三层防护涂层。