关封的英文：
customs seal

seal是什么意思：
n. 海豹；图案，印章；封印；保证，誓约；标志，象征
v. 保证；密封；确定；盖章；密封

A stamp or seal meant to be impressed.
图章用来盖戳的图章或印章

The experience seals their friendship.
这一经历确定了他们的友谊。

Sealing is prohibited in many countries.
许多国家禁止捕海豹。

The probe unit is hermetically sealed.
探头装置是密封的。

It was stored in a tube with a break seal.
它保存在一个有断裂密封垫的试管里。