Entertaiment is a very broad concept and can include anything that affords pleasure, diversion or amusement. It may also refer to a particular performance of some kind. One of the most famous entertainments is Scheherazade, a story in the Persian professional storytelling tradition that is so powerful it has inspired multiple orchestral works; several film adaptations; and an innovative video game.
The experience of entertainment has become strongly associated with amusement, so that it’s not uncommon for people to understand the idea to mean fun and laughter — although many types of entertainment also have a serious purpose, such as in the various forms of ceremony, party, religious festival, or satire. You may see the word abbreviated to entmt on a flier or in industry news publications, but it’s not common for this to happen outside of these specific circumstances.