husk, nut shell
殻 centers on a hard outer covering that encloses and protects something inside: a husk, shell, or similar casing.
殻 combines 壳 (which historically relates to a hard outer covering) with 殳 (a hand holding a tool), suggesting the action of striking or removing a husk or shell.
The left side 壳 looks like a hard shell covering something, and the right side 殳 shows a hand with a tool, as if cracking open a nut to get the kernel inside.
For カク, imagine cracking a nut shell with a sharp 'crack' sound: crack -> カク, and the husk splits open.
shell; husk; hull; pod; chaff
seashell; shell
(Earth's) crust
cast-off skin (snake, insect, etc.); husk; empty shell; exuvia; exuviae
carapace; shell; crust
cigarette end; cigarette butt; tobacco ashes
completely empty (of a residence, etc.); vacant; deserted
eggshell
rice husks; chaff
red iron oxide; red ocher
scale insect
cottony cushion scale (species of scale insect, Icerya purchasi)
crab shell (often ground or crushed and used as fertilizer); crab shell meal
coconut shell
sea shell
grounds (of tea and coffee)
grounds (of tea and coffee)
skeleton shrimp (Caprella mutica); spectre shrimp; specter shrimp
eggshell
bivalves