封印，将内部物质封存以防止其外泄

1. seal

noun (common) (futsuumeishi)

在信封等封口处盖章或粘贴印花税票的行为。亦指该印章或印花税票本身。

2. to seal (e.g. a letter), to affix a seal, to seal up

noun or participle which takes the aux. verb suru