n.

1. 表達；表示[U][C][（+of）]
   I sent them flowers as an expression of thanks.

   我給他們送去鮮花表示感謝。

   the free expression of ideas

   自由發表意見

2. 表情；臉色；聲調[C][U]
   There was no expression on her face.

   她臉上毫無表情。

3. 表現力[U]
4. 措辭；詞句[C]
   "Shut up" is not a polite expression.

   "住口"不是有禮貌的話。

5. 榨出，擠壓[U]
6. 【數】式；符號[C]

n.

1. the action of expressing something.
2. a look on someone's face that conveys a particular emotion.
3. a word or phrase expressing an idea.
4. Mathematics  a collection of symbols that jointly express a quantity.