#topic__subject__issue__matter  some situation or event that is thought about; "he kept drifting off the topic"; "he had been thinking about the subject for several years"; "it is a matter for the police"
  supertype:  #cognitive_content__cognitivecontent__content__mental_object  the sum or range of what has been perceived, discovered, or learned
  subtype:  #res_judicata__resjudicata__res_adjudicata__resadjudicata  a matter already settled in court; cannot be raised again
  subtype:  #area.topic  a subject of study; "it was his area of specialization"; "areas of interest include..."
     subtype:  #gray_area__grey_area  an intermediate area; a topic that is not clearly one thing or the other
     subtype:  #territory  an area of knowledge or interest; "his questions covered a lot of territory"

No statement uses or specializes #topic; click here to add one.