Definition of "fifth" []

• The ordinal number matching the number five in a series. (noun)
• One of five equal parts. (noun)
• One fifth of a gallon or four fifths of a quart of liquor. (noun)
• Music A tone five degrees above or below a given tone in a diatonic scale. (noun)
• Music The interval between two such tones. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Why are four of the stars one color, while the fifth is a different color?"
• "Four of the seats in question are currently held by Democratic incumbents, fighting off Republican challengers; the fifth is the open seat in Chicago's north suburbs vacated by Republican Mark Kirk, who is running for U.S. Senate."
• "I wrote full time for several years (I have published four novels in the UK and my fifth is about to be submitted) having written my first two and half novels while working full-time as an attorney."