Technical term used in physics and chemistry for orbital shells. Often appears in compounds like 電子殻 (electron shell).
See also: 電子殻
Electron shells represent the orbits of electrons around the atomic nucleus.
carapace; shell; crust
eggshell
sea shell
outer shell; crust
The kanji 殻 means 'shell' or 'husk'. The reading かく is used in technical contexts, likely derived from the on'yomi.