The definition should consist of two paragraphs at most. The first sentence of the first paragraph should show the headword(s) in boldface (as in Wikipedia). The first paragraph should basically contain the definition of the term. A second paragraph may be added for further explanation or contextualization.
If the use of a term is restricted to a certain area of linguistics, this is best indicated by the first adverbial expression of the first sentence, e.g.
- "In Ancient Greek linguistics, an augment is a prefix (or sometimes a stem change) that serves to mark past tense."
- "In Functional Grammar, a satellite is an expression not required by the predicate that gives additional optional information about a state of affairs."
If the term is not considered the best available term for the concept that it denotes, instead of a definition the first sentence should contain the expression "...is a synonym of X", e.g.