extra

nouns

a minor actor in crowd scenes
an additional edition of a newspaper (usually to report a crisis)
is a type of (narrower)
an issue of a newspaper
"he read it in yesterday's edition of the Times"
something additional of the same kind
"he always carried extras in case of an emergency"

adjectives

more than is needed, desired, or required
"trying to lose excess weight"; "found some extra change lying on the dresser"; "yet another book on heraldry might be thought redundant"; "skills made redundant by technological advance"; "sleeping in the spare room"; "supernumerary ornamentation"; "it was supererogatory of her to gloat"; "delete superfluous (or unnecessary) words"; "extra ribs as well as other supernumerary internal parts"; "surplus cheese distributed to the needy"
added to a regular schedule
"a special holiday flight"; "put on special buses for the big game"
further or added
"called for additional troops"; "need extra help"; "an extra pair of shoes"

adverbs

unusually or exceptionally
"an extra fast car"