fourth 
(fôrth)
(fôrth)n.
1. The ordinal number matching the number four in a series.
2. One of four equal parts.
3. Music
a. A tone four degrees above or below a given tone in a diatonic scale.
b. The interval between two such tones.
c. The harmonic combination of these tones.
d. The subdominant of a scale or key.
4. The transmission gear or gear ratio used to produce forward speeds next higher to those of third in a motor vehicle.
5. Fourth The Fourth of July; Independence Day. Used with the: went to a parade on the Fourth.
[Middle English fourthe, from Old English fēortha; see kwetwer- in the Appendix of Indo-European roots.]
fourth adv. & adj.
- fallowness
- fall prey to
- Fall River
- Falls
- fall short
- fall through
- fall through the cracks
- fall to
- fall to pieces
- Fallujah
- fall upon
- false
- false alarm
- false arrest
- false color
- false-color
- false consciousness
- false face
- false friend
- false fruit
- false-hearted
- false-heartedness
- false hellebore
- falsehood
- false imprisonment