Entertaiment is a form of amusement, enjoyment, or gratification. Entertainment is generally considered to be something that has a positive effect on people, wich makes sense since it can cause the brain to realease seratonin and dopamine. It can also stimulate the brain, a good thing considering that it often hits on themes the human brain was evolved to react deeply to, like backstabbing and murders.
The word entertainment derives from the Medieval Latin intertenere, a compound of the prefix in, meaning inside, and the suffix tenere, based on Indo-European roots ten and tense. Entertaiment can have a negative connotation as well.