The word 'storybook' is a transparent Modern English compound, formed by combining two native elements. 'Story' entered English via Anglo-French from Latin historia, originally meaning a narrative of past events. 'Book' has a deep Germanic lineage, from the Old English bōc, referring to a written document or set of pages. The compound logically denotes a book whose primary content is a narrative, a concept that became particularly associated with illustrated tales for children in the 19th century. Its formation follows the common English pattern of combining two free morphemes to create a new, specific meaning.

Structure: story (narrative) + book (bound volume) - story: From Anglo-French estorie, from Latin historia (history, narrative). The functional role is the core semantic element, denoting the content. - book: From Old English bōc (book, writing, document), from Proto-Germanic bōks. The functional role is the classifier, denoting the physical format or container.