I see that your reading incomprehension still persists First of all In general Wikipedia articles should rely on reliable secondary sources This does nt mean tertiary sources are nt reliable And General encyclopedias like the Encyclopedia Britannica or Encarta sometimes have authoritative signed articles written by specialists and including references However unsigned entries are written in batches by freelancers and must be used with caution is written under the part Advice specific to subject area and History In other words Encyclopedic sources and hence dictionaries are reliable sources especially when we are nt discussing a historic subject such as this one I do hope that you develop your reading comprehension Try to read lots of books