extra

adj. Additional; more than usual or necessary or expected. adv. 1 more than usually. 2 additionally (was charged extra). n. 1 extra thing. 2 thing for which an extra charge is made. 3 person engaged temporarily for a minor part in a film. 4 special issue of a newspaper etc. 5 cricket run scored other than from a hit with the bat. [probably from *extraordinary]

a. Beyond what is due, usual, expected, or necessary; additional; supernumerary; also, extraordinarily good; superior; as, extra work; extra pay.