A "prop" is an object used in a play, movie, or other performance to help tell a story. It can be something held, used, or displayed by actors to make their characters more realistic and the story more believable. Full definition
One of the most notable is the proliferation of prop bets for just about every conceivable aspect of the game. (sbnation.com)
While these blankets are not as thick as some I've used in studios, they are still versatile to use as props for support and warmth. (yogaaccessories.com)
There are several problems with these types of prop bets including small limits, high juice and the long delays for potential payouts. (sportsinsights.com)