are subgenres and/or themes of any kind (i.e.: Romantic Comedy, Friendship, World War II, Sports, and so on.) that enable you to define more specifically
the plot of the movie you are looking for. Topics are not keywords. Topics are movies about something. Keywords are movies with something. If you search for a given topic, "shark" for example, only movies in which a shark play a significant roll will appear, such as 'Jaws', not every movie that has a shark in it.