A description is about giving the characteristics or visual aspects of something, without adding a value judgement. A description is either done in writing, or orally. Description is one of four Rhetorical modes, the other three are exposition, argumentation, and narration. In logic and philosophy, there is the concept of definite description: It is used to describe something that exists exactly once. Famous mathematicians such as Bertrand Russell or Gottlob Frege wrote about it.