1、define：v.解释(词语)的含义; 给(词语)下定义; 阐明; 明确; 界定; 画出…的线条; 描出…的外形; 确定…的界线;第三人称单数：defines 现在分词：defining 过去式：defined 过去分词：defined。

2、例句：We were unable to define what exactly was wrong with him.我们说不清楚他到底哪里不对劲。