
1) Music book
Found on
https://www.crosswordclues.com/clue/choirbook

A Choirbook is a large format manuscript used by choirs in churches or cathedrals during the Middle Ages and Renaissance. The book is large enough for the entire choir to read from one book. Often for polyphonic works all the musical parts or voices of a piece of music are presented on a single pair of pages, in contrast to partbook, where each pa...
Found on
http://en.wikipedia.org/wiki/Choirbook

(from the article `score`) ...score dates from the schools of polyphony (many-voiced music) in the early Middle Ages but declined during the 13th–16th century. At the beginning ...
Found on
http://www.britannica.com/eb/a-z/c/76
No exact match found.