1. The next in order to the seventy-ninth; the eighth tenth; one of eighty equal parts.

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

• eighttenth,
• eightth,
• eighteeth,
• eightenth,
• eightien,
• eighteth,
• wightieth,
• sightieth,
• dightieth,
• rightieth,
• 4ightieth,
• 3ightieth,
• eughtieth,
• ejghtieth,
• ekghtieth,
• eighieth,
• eightiet,
• eigthieth,
• eightyeth,
• ametheth

• eighteenth,
• eighty-three,
• eighty-two.

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

The plural form of the word "eightieth" is "eightieths".

The singular form of "eightieth" is "eightieth".