Definition of "fourth" []

• The ordinal number matching the number four in a series. (noun)
• One of four equal parts. (noun)
• Music A tone four degrees above or below a given tone in a diatonic scale. (noun)
• Music The interval between two such tones. (noun)
• Music The harmonic combination of these 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.

• "Thus, 104603 means that we place a pig in the first row of the _first_ column, in no row of the _second_ column, in the fourth row of the _third_ column, in the sixth row of the _fourth_ column, in no row of the _fifth_ column, and in the third row of the"
• "The term fourth estate is frequently attributed to the nineteenth century historian Carlyle, though he himself seems to have attributed it to Edmund Burke: Burke said there were Three Estates in Parliament; but, in the Reporters 'Gallery yonder, there sat a Fourth Estate more important than they all."
• "Thus far we have treated of the meaning of the term fourth dimension as it is used in mathematics."