extra

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective More than or beyond what is usual, normal, expected, or necessary: synonym: superfluous.
• adjective Subject to an additional charge.
• noun Something more than is usual or necessary.
• noun Something, such as an accessory on a motor vehicle, for which an additional charge is made.
• noun A special edition of a newspaper.
• noun A performer hired to play a minor part, as in a crowd scene in a film.
• adverb To an exceptional extent or degree; unusually.

from The Century Dictionary.

• Beyond the ordinary standard or measure; extraordinarily; unusually; uncommonly: as, this is done extra well; that is an extra high price.
• More than what is usual, or than what is due, appointed, or expected; supplementary; additional; supernumerary: as, an extra price; an extra edition of a newspaper; extra diet; extra charges at a boarding-school.
• noun Something in addition to what is usual or expected; something over and above the usual course or charge, or beyond what is usual.
• noun Specifically An edition or a copy of a newspaper issued at an unusual hour to convey special intelligence.
• noun In cricket, a score or run not made from the bat, as a bye or a wide: usually in plural.
• A prefix of Latin origin, originally an adverb and preposition, meaning ‘outside, beyond.’ ;
• Used in trade to denote a size somewhat larger than that, mentioned: as, extra elephant folio; extra foolscap octavo.

from the GNU version of the Collaborative International Dictionary of English.

• noun Something in addition to what is due, expected, or customary; esp., an added charge or fee, or something for which an additional charge is made.
• noun An edition of a newspaper issued at a time other than the regular one.
• noun (Cricket) A run, as from a bye, credited to the general score but not made from a hit.
• noun Something of an extra quality or grade.
• adjective Beyond what is due, usual, expected, or necessary; additional; supernumerary; also, extraordinarily good; superior

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Beyond what is due, usual, expected, or necessary; extraneous; additional; supernumerary.
• adjective Extraordinarily good; superior; as extra work, extra pay.
• adverb informal To an extraordinary degree.
• noun cricket A run scored without the ball having hit the striker's bat - a wide, bye, leg bye or no ball; in Australia referred to as a sundry
• noun an extra edition of a newspaper, which is printed outside of the normal printing cycle
• noun A supernumerary or walk-on in a film or play

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun something additional of the same kind
• adjective more than is needed, desired, or required
• adjective further or added
• noun a minor actor in crowd scenes
• adjective added to a regular schedule
• adverb unusually or exceptionally
• noun an additional edition of a newspaper (usually to report a crisis)