Definitions for "Quire"
See Choir.
Archaic term for Eastern end of nave just past the crossing, usually reserved for choristers and priests during the service. More usual term is choir. Church people like to use quaint sounding terms for this area, including chancel (meaning "screened off"), and presbytery (reserved for priesthood - monastic term, obviously).
As Choir - The area of the church where the choristers and clergy sit
A collection of twenty-four sheets of paper of the same size and quality, unfolded or having a single fold; one twentieth of a ream.
A group of leaves folded together prior to binding
A quire consists of eight leaves (which equates to sixteen pages). Every 16th page of each will in PROB 11 is given a quire number.
Quires are the "gatherings" or "booklets" of which a book is formed.
a collection of all of the signatures needed to form a single book, arranged in order
(or Gathering): A group of usually four bifolios assembled to form a booklet. A manuscript is typically composed of several quires sewn and bound together.
Keywords:  concert, sing
To sing in concert.