The cardinal number occurring after seventeen and before nineteen, represented in Roman numerals as XVIII and in Arabic numerals as 18.

plural of eighteen

A surname.

The number one thousand eight hundred. / The start of the nineteenth hour of the day on the 24-hour clock i.e. 18:00. / The year 1800.

The period of time consisting of the years 1800 through 1899.

Alternative spelling of 18-wheeler.

plural of eighteen-wheeler

Synonym of free, white, and twenty-one

The ordinal form of the number eighteen.

The person or thing in the eighteenth position. / One of eighteen equal parts of a whole. / (informal) A party to celebrate an eighteenth birthday.