Entertaiment is a word that has multiple meanings. In general, it describes a show that is put on for the purpose of entertainment. This show can be anything from a play to a reality tv show. Generally, this shows touch on the social backstabbing and murder themes that the human brain was evolutionarily shaped to deeply respond to. This stimulation of the brain causes seratonin and dopamine to be released.
You might see this word abbreviated to entmt on fliers or in industry news publications when space is at a premium. It can also be found in shorthand note taking. The story of Scheherazade, the Persian professional storytelling tradition of a woman who saves her life by telling stories, is a classic example of an entertainer that has inspired a wide range of other entertainment media.