define
/dɪˈfaɪn; dɪ`faɪn/ v
1 [Tn, Cn.n/a]
~ sth (as sth) state precisely the meaning of (eg words) 给（词语等）下定义.
2 [Tn, Tw] state (sth) clearly; explain (sth) 阐明（某事）; 解释（某事）
The powers of a judge are defined by law. 法官的权力是由法律规定的.
It's hard to define exactly what has changed. 很难解释清楚到底发生了什麽变化.
3 [Tn] show (a line, shape, feature, etc) clearly; outline 清楚地显示出（线条、 形状、 特徵等）; 画出...的轮廓
When boundaries between countries are not clearly defined, there is usually trouble. 国与国的边界未明确划定则通常会发生纠纷.
The mountain was sharply defined against the eastern sky. 那座山在东方天空的衬托下显得轮廓分明.
a well-defined profile 轮廓清晰的侧面像.