Abbr. qr. or q. A set of 24 or sometimes 25 sheets of paper of the same size and stock; one twentieth of a ream.
A collection of leaves of parchment or paper, folded one within the other, in a manuscript or book.
[Middle English quayer, four double sheets of paper, from Old French quaer, from Vulgar Latin *quaternus, from Latin quaternī, set of four, four each, from quater, four times; see kwetwer- in Indo-European roots.]