paper-shell
/ˈpeɪpəʃɛl/adjective
1Relating to or designating a crab (or other crustacean) whose shell has not yet fully hardened after moulting.
2Designating an almond or pecan nut with a thin shell.
noun
1A crab (or other crustacean) whose shell has not yet fully hardened after moulting.
2A thin-shelled almond or pecan.
Origin
Late 19th century; earliest use found in George Goode (1851–1896). From paper + shell.