The Collaborative International Dictionary of English v.0.48:

Monograph \Mon"o*graph\, n. [Mono- + -graph.]
   A written account or description of a single thing, or class
   of things; a special treatise on a particular subject of
   limited range.
   [1913 Webster]

WordNet (r) 3.0 (2006):

monograph
    n 1: a detailed and documented treatise on a particular subject

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "monograph":
   article, causerie, descant, discourse, discussion, disquisition,
   dissertation, essay, etude, examination, excursus, exposition,
   feature, first approach, homily, introductory study, lucubration,
   memoir, morceau, note, outline, pandect, paper, paragraph, piece,
   preliminary study, prolegomenon, research paper, screed, sketch,
   special article, study, survey, term paper, theme, thesis, tract,
   tractate, treatise, treatment