chapter
n. countablen. one of the main parts that a book is divided into. It can also mean a specific period of time in a person's life or in history.
n. a main division of a book or other written work, typically numbered or titled. It may also refer to a distinct period or sequence of events in history or a personal narrative.
I am reading the third chapter of the book now.
The final chapter of the biography focuses on the author's later years and her move to the countryside.
While the treaty marked the end of the war, it also opened a difficult new chapter in the region's history as the population struggled to rebuild.
From Middle English chapitre, from Old French chapitre, from Latin capitulum (“a chapter of a book, in Medieval Latin also a synod or council”), diminutive of caput (“a head”); see capital, capitulum, and chapiter, which are doublets of chapter.
Often used with the preposition 'of' to indicate the book or period it belongs to.