1. Eight and ten united.

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

• eoghteen,
• eighte,
• eighteeen,
• nighteen,
• fighten,
• eighten,
• lightern,
• eightenn,
• lighteen,
• eieghteen,
• eitghteen,
• eightteen,
• eithteen,
• eichteen,
• eighted,
• eghteen,
• eigteen,
• mighten,
• kighten,
• eaghteen

• eighth note,
• eighty-nine,
• lighten,
• eighteenth,
• tighten,
• eaten,
• eighty,
• heighten,
• eighty-one,
• eight.

The adjective form of the word "eighteen" is "eighteenth".

The plural form of the word "eighteen" is "eighteens"

The singular form of the word "eighteen" is "eighteen".