The Collaborative International Dictionary of English v.0.48:

Rubric \Ru"bric\, n. [OE. rubriche, OF. rubriche, F. rubrique (
   cf. it. rubrica), fr. L. rubrica red earth for coloring, red
   chalk, the title of a law (because written in red), fr. ruber
   red. See red.]
   That part of any work in the early manuscripts and typography
   which was colored red, to distinguish it from other portions.
   Hence, specifically:
   (a) A titlepage, or part of it, especially that giving the
       date and place of printing; also, the initial letters,
       etc., when printed in red.
   (b) (Law books) The title of a statute; -- so called as being
       anciently written in red letters. --Bell.
   (c) (Liturgies) The directions and rules for the conduct of
       service, formerly written or printed in red; hence, also,
       an ecclesiastical or episcopal injunction; -- usually in
       the plural.
       [1913 Webster]

             All the clergy in England solemnly pledge
             themselves to observe the rubrics.   --Hook.
       [1913 Webster]
   (d) Hence, that which is established or settled, as by
       authority; a thing definitely settled or fixed. --Cowper.
       [1913 Webster]

             Nay, as a duty, it had no place or rubric in human
             conceptions before Christianity.     --De Quincey.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rubric \Ru"bric\, v. t.
   To adorn ith red; to redden; to rubricate. [R.] --Johnson.
   [1913 Webster] Rubric

The Collaborative International Dictionary of English v.0.48:

Rubric \Ru"bric\, Rubrical \Ru"bric*al\, a.
   1. Colored in, or marked with, red; placed in rubrics.
      [1913 Webster]

            What though my name stood rubric on the walls
            Or plaistered posts, with claps, in capitals?
                                                  --Pope.
      [1913 Webster]

   2. Of or pertaining to the rubric or rubrics. "Rubrical
      eccentricities." --C. Kingsley.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rubric
    n 1: an authoritative rule of conduct or procedure
    2: an explanation or definition of an obscure word in a text
       [syn: gloss, rubric]
    3: directions for the conduct of Christian church services
       (often printed in red in a prayer book)
    4: a heading that names a statute or legislative bill; may give
       a brief summary of the matters it deals with; "Title 8
       provided federal help for schools" [syn: title, statute
       title, rubric]
    5: a title or heading that is printed in red or in a special
       type
    6: category name; "it is usually discussed under the rubric of
       `functional obesity'"
    v 1: adorn with ruby red color

Moby Thesaurus II by Grady Ward, 1.0:

200 Moby Thesaurus words for "rubric":
   Sefer Torah, Torah, Torah scroll, Virginal, abbreviation,
   abbreviature, abrege, abridgment, abstract, act, appellation,
   appellative, banner, banner head, basis, bill, blood, bracket,
   branch, breviary, brief, burden, bylaw, canon, capsule, caption,
   case, caste, category, chapter, church book, clan, class, code,
   cognomen, commandment, compend, concern, condensation,
   condensed version, conspectus, convention, decree, denomination,
   designation, dictate, dictation, dictum, digest, division, draft,
   drop head, dropline, edict, enactment, epigraph, epitome, essence,
   estate, euchologion, euchology, farse, focus of attention,
   focus of interest, form, formality, formula, formulary,
   general principle, gist, golden rule, grade, group, grouping,
   guideline, guiding principle, hanger, head, heading, headline,
   imperative, incarnadine, institution, issue, jump head, jus, kin,
   label, law, lectionary, legend, legislation, level, lex, litany,
   living issue, machzor, main point, manual, matter, matter in hand,
   maxim, measure, meat, memorable, missal, mitzvah, moral, motif,
   motive, motto, nomen, norm, notable, observable, order, ordinal,
   ordinance, ordonnance, outline, overline, overview, pandect,
   pigeonhole, point, point at issue, point in question, pontifical,
   position, prayer book, precis, predicament, prescript,
   prescription, principium, principle, problem, question, race, rank,
   rating, red-letter, regulation, review, ritual, rituale, rubify,
   ruby, ruddle, ruddy, rule, ruling, running head, running title,
   scarehead, screamer, section, sept, service book, set,
   settled principle, shortened version, siddur, skeleton, sketch,
   spread, spreadhead, standard, standing order, station, status,
   statute, strain, stratum, streamer, style, subdivision, subgroup,
   subhead, subheading, subject, subject matter, subject of thought,
   suborder, substance, subtitle, superscription, survey, syllabus,
   synopsis, tenet, text, theme, thumbnail sketch, title, title page,
   topic, topical outline, working principle, working rule



Bouvier's Law Dictionary, Revised 6th Ed (1856):

RUBRIC, civil law. The title or inscription of any law or statute, because
the copyists formerly drew and painted the title of laws and statutes rubro
colore, in red letters. Ayl. Pand. B. 1, t. 8; Diet. do Juris. h.t.