Entertaiment is amusement or distraction–the clown at the birthday party, the Broadway show, your friends fighting over the last potato chip. It comes from the Old French entretenir, meaning to keep together or support, originally associated with hospitality–keeping guests happy. Theatrical entertainment is shows, visual entertainment is stuff you like to look at and audio entertainment is music.
The word is often abbreviated to entmt on fliers, in industry news publications and in short hand note taking. But it is rare for it to be abbreviated in general prose. It does appear to be commonly used in business to consumer marketing as a way to draw attention and shorten the text. The six elements of the entertainment can be defined as objective, communication, external stimulus, pleasure, audience and passivity.