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