chapter (n.) Look up chapter at Dictionary.com
c.1200, "main division of a book," from Old French chapitre (12c.) "chapter (of a book), article (of a treaty), chapter (of a cathedral)," alteration of chapitle, from Late Latin capitulum, diminutive of caput (genitive capitis) "head" (see capitulum). Sense of "local branch" (1815) is from cathedral sense (late 15c.), which seems to trace to convocations of canons at cathedral churches, during which the rules of the order by chapter, or a chapter (capitulum) of Scripture, were read aloud to the assembled. Chapter and verse "in full and thoroughly" (1620s) is a reference to Scripture.