kahdenkymmenen

Kahdenkymmenen is a Finnish numeral form meaning "of twenty" or used in constructions corresponding to "twenty" in English. It functions grammatically as a genitive (and appears in other case contexts when combined with nouns) of the compound numeral for twenty and is commonly used in time expressions, measurements and quantified noun phrases.

The form reflects Finnish numeral morphology: it is built from the element for two (kahden, genitive of kaksi) and ten (kymmenen). As a result, kahdenkymmenen appears before a noun to indicate a quantity of twenty, for example kahdenkymmenen hengen ryhmä ("a group of twenty people") or kahdenkymmenen vuoden kuluttua ("after twenty years"). In such phrases the following noun typically takes its own case (often genitive or partitive) according to Finnish grammar.

Kahdenkymmenen is part of a broader pattern in Finnish where compound numerals decline and their stems change depending on case and syntactic context. Usage follows standard rules for numerals in Finnish and may combine with case endings when used on its own in predicative or adverbial roles. It is an everyday lexical item in Finnish and appears across spoken and written registers whenever quantities around twenty are expressed.