The act of entertaining.
Entertainment can be defined by six elements: it is understood objectively, communicates between text and audience, is created from external stimulus, offers pleasure, requires an audience to exist and occurs in a passive form. (Oliver and Barstsch 2010).
Entertainment stimulate the brain to realease seratonin and dopamine. It often hits on themes the human mind was evolved to react deeply to in order to survive in the social world. Like murders, backstabbing and other social themes.
Entertainment can be found in many different forms and cross over multiple media. This makes it a highly re-used and recognizable form in the culture.