breviary

Breviary goes back to Latin brevis, "short." Medieval Latin formed breviarium for an abridgment, summary, or concise manual. The word did not begin as a sacred object. It began as a compact text, a shortened gathering of material.

By the early Middle Ages, church use narrowed the term. A breviarium became the book containing the daily offices for clergy and monastic communities. The title fit because the volume condensed psalms, prayers, readings, and rubrics into an ordered whole. What was brief was not the worship itself, but the gathered handbook.

The word moved through Anglo-Norman and ecclesiastical French into English by the 15th century. In England it appeared as breviary for the service book of the Roman rite and related traditions. The term lived in a world of manuscripts, choirs, and fixed hours of prayer. It named both a physical book and the system it carried.

Modern English still uses breviary mostly in religious and historical contexts. It can mean the liturgical book itself, and by extension a concise handbook in a figurative sense. The figurative use is rare but faithful to the older Latin pattern. A brief book became a book of hours.