blue book

== English == === Etymology === The term dates back to the 15th century, when large blue velvet-covered books were used for record-keeping by the Parliament of the United Kingdom. === Noun === blue book (plural blue books) A book of statistics or almanac, usually published by an agency or as a trade publication. Used other than figuratively or idiomatically: see blue,‎ book. ==== See also ==== Project Blue Book blue book exam