in Latin, The Genetive case is that which is used to show poessession.

For Example:
English: "The woman's house is beautiful."
Latin: "casa feminae pulchra est."

English: "The women's houses are beautiful."
Latin: "casae femeniarum sunt pulchrae."

In Latin, the Genetive case uses the endings:
      Sing  Plur
1Dec   -ae   -arum
2Dec   -i    -orum
3Dec   -is   -um*
4Dec   -us   -uum
5Dec   -ei   -erum

* - Third Declension plural Nouns can have what's called an 'i-stem' that makes the plural form '-ium'...

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