Orismology

Orismology is the study of the process and the products of definition, in practice, in praxis, and in theory. "Orismology" is particularly applicable to the analysis and the writing of stipulative, normative definitions that explain and delimit the use of technical terms. The word is constructed from the Greek: "orismos" (definition) and "logos" (word, reasoning, study). 
History.
The word was coined by William Kirby and William Spence in their "Introduction to Entomology" in the early 1800s: "In the "terminology", or what, to avoid the barbarism of a word compounded of Latin and Greek, [Kirby and Spence] would beg to call "orismology" of the science, they have endeavoured to introduce throughout a greater degree of precision and concinnity" in the terms used to talk about insects. This approach to definition is particularly applied to disciplines in natural sciences like Kirby and Spence's entomology that depend upon classificatory schemes, such as taxonomies and ontologies, to organize, name, and address their subject matter. Since the emergence of the discipline of terminology, the use of "orismology" has been specialized to definitions and returned to its Greek roots. In the construction of glossaries, that is, specialized dictionaries within a specified domain of discourse, "orismology" is generally taken as the complement of "nomenography", the study of terms necessary and sufficient for discourse within a specified domain.
The "Imperial Dictionary" (1882) reported: "that branch of natural history which relates to the explanation of the technical terms of the science."
The "Oxford English Dictionary" (1909) reported: "A name for the explanation of technical terms, or for such terms collectively; terminology."
In Elk's view, "orismology" includes etymology and should not be confused with terminology, which focuses on current and immediate interpretations of words. He gives this example: The drug name "penicillin" was coined by Alexander Fleming from the Latin for "paintbrush", which is "penicillus". "Methicillin", a type of penicillin, gained its name by attaching the stem "-cillin" (from the United States Adopted Names Council's list of stems) to a prefix "meth" which has no inherent meaning. The study of penicillin and methicillin individually would be an etymological study of terminology. However, the study of methicillin as its name derived from penicillin historically might best be described, according to Elk, as "orismologic". Elk's use of the words "orismology" and "terminology" echo the historical notions of Kirby and Spence rather than modern disciplinary senses of these words. Orismology does not entail etymology, but nomenography may well delve into etymological analysis to construct such neologisms as are needed to satisfy logical requirements for terms within a domain of discourse. Orismology and nomenography are studies overlapping both terminology and specialized lexicography.