1 envelope

2 outer shell

3 hull

4 cover

5 case

1 shell

2 carapace

3 crust (earth's crust etc)

4 also pr. [ké]

1 tortoise

2 cuckold

1 skull

2 (fig.) brain (mental capacity)

1 shell

2 conch

3 cowry

4 mother of pearl

5 hard outer skin

6 also pr. [bèi qiào]

1 like mice trying to pull a turtle, nowhere to get a hand grip (idiom)

2 no clue where to start

1 lit. the cicada sheds its carapace (idiom); fig. to vanish leaving an empty shell

2 a crafty escape plan

1 lit. a tortoise laughing at a soft-shelled turtle for having no tail (idiom)

2 fig. the pot calling the kettle black