extra

adjective

more, larger, or better than is expected, usual, or necessary; additional or superior
requiring payment of an added charge

noun

an extra person or thing; specif.,

an additional charge: often used in pl.
☆ a special edition of a newspaper as formerly put out between regular editions to cover news of unusual importance
an additional benefit or feature
a spare or leftover copy of something
an extra worker
Cricket a run not made from a hit, as a bye
Film an actor hired by the day to play a minor part, as a member of a crowd scene, etc.

adverb

more than usually; esp., exceptionally: extra good quality

See extra in American Heritage Dictionary 4