Stirling number of the second kind

Noun

 * 1)  The number of ways to partition a set of n objects into k non-empty subsets, denoted by S(n,k).

Translations

 * Finnish: toisen lajin Stirlingin luku, Stirlingin toinen luku
 * German: Stirling-Zahl zweiter Art
 * Polish: liczba Stirlinga II rodzaju