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fifth

(fĭfth, fĭth)

1. The ordinal number matching the number five in a series.

2. One of five equal parts.

3. One fifth of a gallon or four fifths of a quart of liquor.

4. Music

a. A tone five degrees above or below a given tone in a diatonic scale.

b. The interval between two such tones.

c. The harmonic combination of two such tones.

d. The dominant of a scale or key.

5. Fifth The Fifth Amendment. Used with the.

[Middle English, from Old English fīfta; see penk^we in the Appendix of Indo-European roots.]

fifth adv. & adj.

fifthly adv.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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