a.

1. 完全一样的；复制的；副本的
   He opened the door with a duplicate key.

   他用一把复制的钥匙打开了门。

2. 二重的；一对的；二倍的
3. 【牌】复局的

n.

1. 完全一样的东西；复制品；副本[C]
   Keep a duplicate of the letter.

   保存一份信的副本。

2. 【牌】复局

vt.

1. 复制；复写；影印，拷贝
   All the members received duplicated notices of the meeting.

   所有会员都接到同样的会议通知。

2. 重复
3. 使成双；使加倍

adj.

1. exactly like something else, especially through having been copied.
2. having two corresponding parts.

n.

v.