The term "monographia" is derived from the Greek 'mono' (single) and grapho (to write), meaning "writing on a single subject". Unlike a textbook, which surveys the state of knowledge in a field, the main purpose of a monograph is to present primary research and original scholarship. This research is presented at length, distinguishing a monograph from an article. For these reasons, publication of a monograph is commonly regarded as vital for career progression in many academic disciplines. Intended for other researchers and bought primarily by libraries, monographs are generally published as individual volumes in a short print run.
In library science
In librarianship, the word monograph has a broader meaning, that of a nonserial publication complete in one volume (book) or a finite number of volumes, meaning any piece of writing can be described as a monograph. Thus it differs from a serial publication such as a magazine, journal, or newspaper.
In biological taxonomy a monograph is a comprehensive treatment of a taxon. Monographs typically revise all known species within a group, add any newly discovered species, and collect and synthesize available information on the ecological associations, geographic distributions, and morphological variations within the group. Example: Lent & Wygodzinsky, 1979, Revision of the Triatominae (Hemiptera, Reduviidae), and their significance as vectors of Chagas' disease. Bulletin of the American Museum of Natural History v. 163, article 3, pp. 125–520.
In United States Food and Drug Administration regulation
In the context of Food and Drug Administration (FDA) regulation, monographs represent published standards by which the use of one or more substances is automatically authorized. For example, the following is an excerpt from the Federal Register: "The Food and Drug Administration (FDA) is issuing a final rule in the form of a final monograph establishing conditions under which over-the-counter (OTC) sunscreen drug products are generally recognized as safe and effective and not misbranded as part of FDA's ongoing review of OTC drug products." Such usage has given rise to the use of the word monograph as a verb, as in "this substance has been monographed by the FDA".
Book publishers use the term "artist monograph" to indicate books consisting of reproductions of works of art by a single artist, as opposed to surveys of art from multiple artists.
- "'monograph' has become a catch-all term for a book that is not of a reference type, that is of primary material" 
- The Role and Future of the Monograph in Arts and Humanities Research (University College, London)
- Prytherch, Raymond John, Harrod's librarians' glossary and reference book : a directory of over 10,200 terms, organizations, projects and acronyms in the areas of information management, library science, publishing and archive management, 10th edn (Aldershot, Hants, England ; Burlington, VT: Ashgate, 2005), p. 462.
- Vines, Sydney Howard (1913). "Robert Morison 1620—1683 and John Ray 1627—1705". In Oliver, Francis Wall (ed.). Makers of British Botany. Cambridge University Press. p. 22.
- [Federal Register: May 21, 1999 (Volume 64, Number 98)][Rules and Regulations] [Page 27666-27693]From the Federal Register Online via GPO Access [wais.access.gpo.gov][DOCID:fr21my99-6]