define

动词 define:

1. give a definition for the meaning of a word
2. determine the essential quality of
   同义词：specify, delineate, delimit, delimitate
3. determine the nature of
4. show the form or outline of
   同义词：delineate

1. Definitions should not be more difficult to understand than the words they define.
   词语的定义不应比所解释的词语更难理解。
2. When boundaries between countries are not clearly defined, there is usually trouble.
   国与国之间的边界未明确划定时，通常会发生纠纷。
3. The powers of a judge are defined by law.
   法官的权限是由法律规定的。

de.fine

v.（动词）
de.fined,de.fin.ing,de.fines
v.tr.（及物动词）

To state the precise meaning of (a word or sense of a word, for example).
给…下定义：给（例如，单词或词义）下精确的定义
To describe the nature or basic qualities of; explain:
阐释：描述…的性质或基本特征；解释：
例句：
define the properties of a new drug; a study that defines people according to their median incomes.
解释一种新药的特性；根据人们的平均收入阐释的调查

To delineate the outline or form of:
勾画出…的轮廓或外形：
例句：
gentle hills that were defined against the sky.
在天空的衬托下显得轮廓分明的丘陵

To specify distinctly:
清楚地规定：
例句：
define the weapons to be used in limited warfare.
明确地规定只能用于局部战争中的武器

To serve to distinguish; characterize:
用于分辨；显示…的特色：
例句：
.portraits that defined the style of an epoch.(Gloria Vanderbilt)
.表现一个时代风格特征的描写.(格洛丽亚·范德比尔特)

v.intr.（不及物动词）
To make or write a definition.
下定义

来源：
Middle English definen, diffinen
中古英语 definen, diffinen
from Old French definir, diffiner
源自 古法语 definir, diffiner
from Latin dôfonore [to limit, determine]
源自 拉丁语 dôfonore [限定，确定]
dô- [intensive pref.] * see de-
dô- [加强语意的前缀] *参见 de-
fonis [boundary, limit]
fonis [边界，界线]

【引伸】
defin.abil.ity
n.（名词）
defin.able
adj.（形容词）
defin.ably
adv.（副词）
define.ment
n.（名词）
defin.er
n.（名词）