more than is due, usual, or necessary; additional

extra work

subject to an additional charge

Room service is extra

something extra or additional, e.g. an added charge or an item for which such a charge is made

somebody extra or additional; specif somebody hired to act in a group scene in a film or stage production

a specified edition of a newspaper

the late-night extra

a run in cricket, e.g. a bye, no-ball, or wide, that is not scored by a stroke of the bat and is not credited to a batsman's individual score: compare bye¹ (2), leg bye