envelope

US /ˈɑːn.və.loʊp/

UK /ˈɑːn.və.loʊp/

信封

a flat, usually square or rectangular, paper container with a gummed flap, used for enclosing a letter or document

•

She sealed the letter in an envelope.

她把信封在信封裡。

•

Please put the documents in a large envelope.

請把文件放在一個大信封裡。

包膜, 外殼

a layer or surrounding part that encloses or covers something

•

The planet is surrounded by a thick gaseous envelope.

這顆行星被一層厚厚的氣體包圍著。

•

The virus has a protective protein envelope.

該病毒具有保護性蛋白質包膜。