Entertaiment is an activity that holds the attention and interest of an audience or gives pleasure and delight. It can be an idea or a task, but is more likely to be one of the activities and events that have developed over thousands of years specifically for this purpose.
Many of these entertainments, such as murders and social backstabbing, hit on themes that our brains were evolved to understand and deeply react to. The word entertain comes from the Medieval Latin intertenere, which combines the prefix inter- (inside) with the suffix -tenere (to hold). It is related to the Indo-European root ten, meaning “stretch.” See also edutainment.