fourth

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The ordinal number matching the number four in a series.
2. n. One of four equal parts.
3. n. Music A tone four degrees above or below a given tone in a diatonic scale.
4. n. Music The interval between two such tones.
5. n. Music The harmonic combination of these tones.
6. n. Music The subdominant of a scale or key.
7. n. The transmission gear or gear ratio used to produce forward speeds next higher to those of third in a motor vehicle.
8. n. The Fourth of July; Independence Day. Used with the: went to a parade on the Fourth.

Century Dictionary and Cyclopedia

1. Next after the third: an ordinal numeral.
2. n. The quotient of unity divided by four; one of four equal parts of anything; a quarter: as, three fourths (¾) of an acre.
3. n. In early English law, a fourth part of the rents of the year, or of movables, or both, granted or levied by way of tax.
4. n. In music A tone four diatonic degrees above or below any given tone.
5. n. The interval between any tone and a tone four degrees distant from it.
6. n. The harmonic combination of two such tones.
7. n. In a scale, the fourth tone from the bottom; the subdominant: solmizated fa, as F in the scale of C, or D in that of A. The typical interval of the fourth is that between the first and fourth tones of a scale, acoustically represented by the ratio 3:4—that is, in number of vibrations— and equal to two diatonic steps and a half. Such a fourth is called perfect or major; a fourth one half step shorter is called diminished or minor; a fourth one half step longer is called augmented, extreme, sharp, or superfluous. The perfect fourth is the second most perfect consonance after the octave, and the next to the fifth.

Wiktionary

1. adj. The ordinal form of number four.
2. n. not used in the plural The person or thing in the fourth position.
3. n. A quarter, one of four equal parts of a whole.
4. n. not used in the plural The fourth gear of an engine.
5. n. music A musical interval which spans four degrees of the diatonic scale, for example C to F (C D E F).

GNU Webster's 1913

1. adj. Next in order after the third; the ordinal of four.
2. adj. Forming one of four equal parts into which anything may be divided.
3. n. One of four equal parts into which one whole may be divided; the quotient of a unit divided by four.
4. n. (Mus.) The interval of two tones and a semitone, embracing four diatonic degrees of the scale; the subdominant of any key.
5. n. One coming next in order after the third.

WordNet 3.0

1. n. the musical interval between one note and another four notes away from it
2. adj. coming next after the third and just before the fifth in position or time or degree or magnitude
3. adv. in the fourth place
4. n. following the third position; number four in a countable series
5. n. one of four equal parts