1. Next after seventh.

2. One of eight equal parts; an interval composed of five tones and two semitones.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• eighte,
• eitht,
• eidth,
• eigth,
• weighth,
• eigthth,
• eighy,
• eaight,
• eghty,
• lighth,
• mighth,
• eith,
• eiwth,
• eightht,
• eightth,
• iight,
• heighth,
• eigher,
• highth,
• eighther

• eight,
• eighty,
• earth.

The adjective form of the word "eighth" is "eighth".

The plural form of the word "eighth" is "eighths"

The singular form of the word "eighth" is "eighth". The word does not change when used in both singular and plural forms.