■ adjective added to an existing or usual amount or number.
■ adverb
1》 to a greater extent than usual.
2》 in addition.
■ noun
1》 an item for which an ~ charge is made.
2》 an ~ item.
3》 a person engaged temporarily to fill out a crowd scene in a film or play.
4》 Cricket a run scored other than from a hit with the bat, credited to the batting side rather than to a batsman.
Origin
C17 (as adjective): prob. a shortening of ~ordinary , suggested by similar forms in Fr. and Ger.