According to Sager’s theory a terminological definition is the explanation of the
specialized meaning of a concept, its essential
characteristics and its classification within a specialized subject field, which can be documented in a variety of sources. In contrast to the general language definitions, where a word is defined by its synonyms and their overlapping meanings, in terminological definitions the term can be defined by the concepts surrounding it in the specialized field it appears. The terminological definition does not have to be exhaustive and self-contained, as the terms can complement each other with the help of terminological relations that relate different term records.
A good terminological definition responds to the need of subject specialists for identification of a new process, as well as to the need of
translators for finding the equivalence of a term. There are various methods used for defining concepts in
terminology, like the definition by analysis, definition by synthesis, etc. There are also rules that govern the formation of terminological definitions, based on either the method or the expression used in the process. These rules can also serve as criteria for examining whether a terminological definition has served its purpose or not, in other words, if it is a good one or not.
More on this issue can be found in Routledge Encyclopedia of Translation Studies that is available at Amazon