n line that marks a border 边界线; 国境线; 分界线
*(fig 比喻) The borderline between informal language and slang is hard to define. 口语和俚语之间的分界线是很难确定的. adj between two different groups or categories 介乎两种组别或类型之间的
*a borderline case 难以确定的两可情况
* a borderline candidate, ie sb who may or may not pass an examination, be suitable for a job, etc 边缘人物（可能及格也可能不及格的考生, 可能胜任也可能不胜任工作等的候选人）
* a borderline pass/failure (in an examination) （考试）在及格与不及格两可的情况下及格[不及格].