Noun
(German grammar) The declension pattern for attributive adjectives that follow the indefinite article ein, the negative article kein, and possessive determiners such as mein and dein.
(German grammar) The declension pattern for masculine and neuter nouns that have -en in the plural but -s, -es, or -ens in the genitive singular.
(Latin grammar) A subtype of the third declension with -ium in the genitive plural.
Source: en.wiktionary.org