XVIIth

XVIIth is the English ordinal form derived from the Roman numeral XVII, indicating the seventeenth item in a sequence. It is used in contexts where Roman numerals signify order alongside an English -th suffix, typically in older or more formal texts, lists, or titles.

In practice, XVIIth appears in historical or ceremonial writing to denote the seventeenth in a succession, such as the XVIIth Dynasty or the XVIIth Regiment. When applied to time, "the XVIIth century" denotes the 17th century, corresponding roughly to the years 1601–1700 in the Gregorian calendar.

Modern usage tends to favor Arabic numerals with the standard ordinal ending (17th) rather than combining a roman numeral with the -th suffix. The form XVIIth is more commonly found in historical documents, older encyclopedias, or stylistic choices intended to evoke antiquity. Writers who prefer contemporary style usually render it as 17th century or XVII without the ordinal suffix, depending on house style.

Cross-linguistically, the equivalent concept exists but is written differently; for example French uses XVIIe for the seventeenth. The general idea—designating succession or era by a seventeenth position or century—remains consistent across styles, even as specific orthography varies.

See also: Roman numerals, ordinals, centuries.