Latin Noun Declension

Declension     gen. sg.     Characteristics
First     -ae     thematic, feminine nouns, some adjectives
Second     -i     thematic, o/e vocalic alternance, masculine and neuter nouns, some adjectives
Third     -is     athematic, all genders, some adjectives; stems ending in a consonant and others in -i
Fourth     -us     thematic, all genders
Fifth     -ei     athematic, small number of feminine nouns