The nominative case, the form listed in the dictionary, is used for the subject of the sentence. The genitive case often shows ownership. The accusative case is used for a direct object, the dative case for an indirect object. The instrumental case is used for the tool or instrument with which something is done. The prepositional case is used after certain prepositions, such as "in" and "on", but other prepositions may require the use of other cases. Each case has other uses than those listed.