|The Simple English Wiktionary has a definition for: description.|
A description is giving the characteristics or look of something. People describe things by writing, or by speaking. Description is one of the four Rhetorical modes, the other three are exposition, argumentation, and narration. Definite descriptions is when somebody describes something once, and the description never changes. Some famous mathematicians, for example Bertrand Russell or Gottlob Frege, wrote about definite descriptions.