18th

The 18th is the ordinal form of the number 18, used to indicate position in a sequence or a time period. It appears in many contexts, including dates (the 18th of a month), lists, chapters, and historical eras, as well as in phrases like the eighteenth century or the eighteenth amendment.

In English, the ordinal is formed from the cardinal eighteen by adding the suffix -th, yielding eighteenth. The abbreviated form in writing or typesetting is 18th. When spelled out, the word is eighteenth. These forms are used consistently in most English-language contexts, with occasional stylistic variants in punctuation or capitalization.

Representations of 18th include the Roman numeral XVIII, which is used in contexts such as monarch regnal numbers or enumerating centuries or events. The 18th letter of the Latin alphabet is R. The ordinal 18th is commonly employed in historical references, legal texts, and academic writings to denote a specific position within a sequence.

Common uses include the eighteenth century (1700s), the eighteenth amendment of a constitution, or “the 18th street” in a street address. The term functions as a practical labeling device across disciplines, from history and law to literature and geography, providing a precise, conventional way to reference order and time.