envelope [英]ˈenvələup [美]ˈɛnvəˌlop,ˈɑn-
n.信封,封皮;壳层,外壳;包裹物;[生物学]膜,包袋
[例句]Inside the empty envelope propped up against a cup.
紧靠在杯子旁的那个空空的信封里面.