IPA: //sʌbˈtʃæptər//
KK: /sʌbˈtʃæptər/
A part of a chapter that is smaller than the whole chapter, often used to organize content in books or legal documents.
The book is divided into several subchapters, each focusing on a different aspect of the topic.
Subchapter → It is formed from "sub-" (meaning under or below) and "chapter" (from Latin "capitulum", meaning a small head or division). The word "subchapter" refers to a division that is under or part of a larger chapter.
Think of a section that is 'under' ('sub-') a larger section or 'chapter' — that's what a subchapter is.