extra
Something additional, such as an item above and beyond the ordinary school curriculum, or added to the usual charge on a bill.
An extra edition of a newspaper, which is printed outside of the normal printing cycle.
Extra, extra! Read all about it!
A run scored without the ball having hit the striker's bat - a wide, bye, leg bye or no ball.
A supernumerary or walk-on in a film or play.
Something of an extra quality or grade.