A discourse, taken in the wide sense of any kind of coherent text (a story, a monologue, a dialogue, a lecture, etc.), is “about” certain entities. […] For those entities about which a certain discourse imparts information we may use the term Discourse Topic (D-Topic). One discourse may have different D-topics, some more central to the discourse than others. D-topics may be hierarchically organized […]. The notion of D-Topic should thus be interpreted relative to the stretch of discourse (book, chapter, section, paragraph, and ultimately the individual clause) under consideration. D-Topics may also be sequentially organized, as when different and possibly even unrelated D-Topics are treated one by one in a sequence of discourse episodes.
- Dik (1989), Pag. 266-267