LatinGrammar

Noun Case

The case of a noun determines the noun's role in the sentence.

Nominative caseSubject of sentence
Accusative caseDirect object of sentence, extent in space or time
Vocative caseCalling or addressing
Genitive caseOwnership
Dative caseIndirect object (to whom or for whom)
Ablative caseAuthorship, use of something as tool (with ...), time when or within which

References

http://mylanguages.org/learn_latin.php