n.[C]

1. 双胞胎之一
   He is the younger twin of the two.

   他是这对双胞胎中的弟弟。

2. 双胞胎；孪生儿[P]
   She gave birth to twins.

   她生了双胞胎。

3. 两个极相似的人（或事物）；两个关系极密切的人（或事物）[P]
4. （有成对单人床的）双人房间
5. 双子星座[the P]

a.[Z][B]

1. 孪生的
   She is Claire's twin sister.

   她是克莱儿的孪生姐妹。

2. 非常相似的；成对的
   The government has to deal with the twin issues of inflation and unemployment.

   政府必须对付通货膨胀与失业这两个密切相关的问题。

3. 双重的
   The plan has a twin purpose.

   这一计划有双重目的。

vt.

1. 使成对；使偶合
2. 使结成姐妹市[（+with）]
   Our city is twinned with Seoul.

   本市与首尔结成姐妹市。

vi.

1. 生双胞胎
2. 成对；偶合[（+with）]

n.

1. one of two children or animals born at the same birth.
2. something containing or consisting of two matching or corresponding parts.

adj.

1. forming or being one of a twin.
2. forming a matching or closely connected pair.
3. (of a crystal) twinned.

v.

1. link; combine.
   ▸Brit. link (a town or district) with another in a different country, for the purposes of cultural exchange.
2. [as adj. twinned] (of a crystal) that is a composite consisting of two (or more) parts which are reversed in orientation with respect to each other.