One of the main divisions of a relatively lengthy piece of writing, such as a book, that is usually numbered or titled. A distinct period or sequence of events, as in history or a person's life: Steamboat travel opened a new chapter in America's exploration of the West. A local branch of an organization, such as a club or fraternity: The Chicago chapter is admitting new members this year. Ecclesiastical An assembly of the canons of a church or of the members of a religious residence. Ecclesiastical The canons of a church or the members of a religious residence considered as a group. A short scriptural passage read after the psalms in certain church services.