Discursivity

Discursivity refers to the quality of being discursive, which can mean a tendency to ramble or wander from one topic to another in speech or writing, or the use of analytical reasoning to move coherently from topic to topic. The term also denotes anything related to discourse (meaning to talk or write, especially in a formal or academic way) or the process of being able to talk about or understand something, as seen in the psychoanalytic concept of discursivity where desire must be expressible in words to be analyzed. 

In summary, discursivity can describe:

• A rambling style: When speech or writing wanders from a main point, covering many subjects in an unorderly fashion. 
• Analytical reasoning: A method of moving from one topic to another in a logical, coherent manner, resolving complex ideas into simpler ones. 
• Expressibility: The capacity for something to be put into words or understood through language, as in psychoanalysis, where a desire must be “discursive” to be analyzed. 
• A formal style: The act of discussing or dealing with topics, sometimes slightly connected to a main subject, in a lengthy or formal manner