IPA: //ˈsʌbˌʃɛl//
KK: /sʌbˌʃɛl/
A group of one or more orbitals within an electron shell of an atom, which can hold electrons.
In chemistry, a subshell is important for understanding how electrons are arranged in an atom.
Subshell → It is formed from "sub-" (meaning under or below) and "shell" (from Old English "scealu", meaning a protective outer covering). The word "subshell" refers to a layer or structure that is beneath another layer or shell.
Think of something that is 'under' ('sub-') another protective 'covering' ('shell') — that's why subshell means a layer beneath another.