eighteenth

num. coming after the seventeenth and before the nineteenth.

num. the ordinal number matching the cardinal number eighteen in a sequence.

“My office is on the eighteenth floor of the building.”

“The eighteenth century was a period of significant intellectual and political upheaval across the European continent.”

n. one of eighteen equal parts of a whole.

n. one of eighteen equal parts into which a whole is divided.

“An eighteenth of the budget was spent on office supplies.”

“The mathematician calculated that each segment represented exactly one eighteenth of the total surface area.”

n. a party to celebrate someone's eighteenth birthday.

n. a social gathering or celebration held in honour of an individual's eighteenth birthday.

“Are you going to Sarah's eighteenth on Saturday night?”

“The venue was fully booked for a local student's eighteenth, resulting in significant noise complaints from the neighbours.”

Informal · British English