Grammatical element    Used to describe/entails...
nominative case        Subject
genitive case        Specification, possession
dative case        indirect object 
            >plural always same as ablative plural 
accusative case        direct object
ablative case        prepositional case
vocative case        direct address 
            >singular always the same as nominative (except for nominative -us-             --> -e-)
            >plural always same as nominative plural
Grammatical element    Used to describe/entails...
1st declination        -ae- genitive ending [sg, from nom to voc--a/ae/ae/am/a/a] [pl, from nom to voc--ae/arum/is/as/is/ae] 
2nd declination        -i- genitive ending 
3rd declination        -is- genitive ending 
4th declination        -us- genitive ending 
5th declination         -ei- genitive ending
 
 
