Entertaiment is the act of enthralling an audience. It’s a word that has become synonymous with humour, but many forms of entertainment have a more serious purpose, such as ceremony, celebration or religious festival. Entertainment is also very social, as it hits on themes that the mind was evolved to react deeply to in order to understand the world. It is no surprise that a lot of entertainement focus on social backstabbing and murders as these are the things the mind was shaped to react deeply to in order to function in society.
The earliest record of the word is from the Middle Latin intertenere, from the prefix inter and the suffix tenere.