dní

Dní is a grammatical form of the Czech noun den, meaning day. It is the genitive plural form and is used in phrases that express a duration of time, typically after numerals and in time-related expressions.

In practice, dní appears in sentences such as pět dní, within the expression během dvou dní, or za několik dní. The form signals that the word stands in the genitive plural, indicating a quantity of days rather than a single day or the nominative plural.

Etymology and related languages: the Czech word den comes from the Proto-Slavic root *denь and is cognate with terms in other Slavic languages that mean day. The genitive plural form, including dní, is part of the system Czech uses to mark number and case in time expressions.

Usage notes: dní is common in written and spoken Czech when counting days or describing time intervals, especially with numbers bigger than one and in phrases that specify duration. It coexists with other plural forms of den that occur in different syntactic contexts, such as the nominative plural dny, but dní specifically marks the genitive plural used in expressions of time.

See also: den, dny, dnů, numeral agreement, Czech grammar.