Rubrics, a name, as printed originally in red ink, applied to the rules and instructions given in the liturgy of the Prayer-Book for regulating the conduct of divine service, hence applied in a wider significance to any fixed ecclesiastical or other injunction or order; was used to designate the headings or title of chapters of certain old law-books and MSS., formerly but not now necessarily printed in red characters.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Rubinstein, Anton * Ruby