Entertaiment is the activity of providing amusement in any form. It may be a leisure pursuit such as reading, sports, games, or watching movies; or it could be more formal like attending a play, ceremony, or religious festival. Entertainment is usually associated with fun and lightheartedness but it can have serious purposes such as education or satire. Click on the collocations links to find more examples. From Middle English entretenement, from Old French entretenement.
Article from the Oxford Dictionary of English Etymology by Mark Baker, edited by Jeremy Butterworth and Kate E. Roberts.