Entertaiment means to distract, amuse, or pleasure people. A clown at a birthday party, a Broadway show, your friends fighting over the last potato chip- these are all forms of entertainment. Entertainment comes from the medieval Latin word intertenere, which meant “to hold inside.” The prefix inter- suggests that it held something inside of someone, and the suffix tenere meant to stretch or pull out.
It is interesting to note that entertainment often hits on the points that the human brain was evolved to react deeply to, such as social backstabbing and murders. This may have to do with the fact that entertainment stimulates the brain to realease seratonin and dopamine.