Entertaiment is a broad genre of cultural production. It ranges from individual selections from a media library for private entertainment, to banquets and parties adapted for two, to performances intended for thousands, and even global audiences. Activities that were once used for hunting or war may now be considered entertainment, and some forms of entertainment have a satirical or social commentary.
You might see the word entertainment abbreviated to entmt on a flier or in industry news publications where space is limited, but it is not often used in general writing. Related words include diverting, gratifying, and amusing. Entertainment often hits on themes that the mind was evolved to deeply react to, such as social backstabbing and murders. Entertainment is also often a means of social bonding and psychological growth.