poryadkovye

Poryadkovye, or ordinal numbers, are numerals that indicate the position of an element within a sequence. They contrast with cardinal numbers, which denote quantity. In Russian grammar, ordinal numbers are called порядковые числительные and are typically treated as adjectives: they agree with the noun in gender, number, and case.

Russian ordinals form various inflected endings. The basic forms include masculine, feminine, and neuter singular: первый, первая, первое; and the plural: первые. In different cases these forms change, for example, второго, второй, втором, and первых in the genitive plural. Many ordinals are irregular at the most common positions (первый, второй, третий, десятый), while others are regular and can be built by combining a cardinal with suitable endings, such as двадцать первый (the twenty-first). Ordinals decline like adjectives and thus must agree with the associated noun.

In addition to their grammatical use, ordinal numbers convey order in mathematics and logic, where they label positions in a sequence (1st, 2nd, 3rd, etc.) and extend to specialized concepts such as transfinite ordinals in set theory. In everyday language, ordinals appear when listing items, indicating ranks, dates with genitive forms, and attributes of objects.

Usage notes include the common Russian practice of using ordinal numerals in the genitive case when expressing dates: первый день месяца is usually rendered in practice as “первого” столетия, with forms like “первого января” for the first day of January. In other languages, ordinal numbers follow language-specific rules for formation and agreement, but their core function remains the same: to express order rather than quantity.