Case Name
and Typical Meaning / Use

Sing./Plural
Endings

Examples

Nominative

The "subject case": the subject is the word found by asking WHO or WHAT before the verb.

[various endings]

-ÊS

rêx, rêgês

Rêx imperium administrat.
  The king administers the power.
 
Rêgês regunt.
  The kings rule.

Genitive

The "possession case": The genitive word corresponds to the word that takes an apostrophe in English. If (A) is in the genitive, (A) possesses something else (B), with the emphasis falling on (B), so that (A) is somewhat like a modifier of (B): in student's book (= discipuli liber), the possession-word qualifies the meaning of the noun book. 

-IS

-UM

rêgis, rêgum

Magna erat rêgis fâma.
  The king's fame was great.
 
Rêgum virtûs valet.
 The excellence of the kings is strong.

Dative

The "indirect object case": the indirect object is found by asking TO / FOR WHOM? or TO / FOR WHAT? after the verb. Certain verbs govern the dative.

-Î

-IBUS

rêgî, rêgibus

Rêgî pecûniam dat.
  He is giving money to the kings.
 
Rêgibus dôna dat populus.
  The people gives gifts to the kings.

Accusative

The "direct object case": the direct object is usually found by asking WHO or WHAT after an action-verb whose action has a receiver. "We hold these truths." The accusative is also used after certain prepositions.

-EM

-ÊS

rêgem,  rêgês

Agricolae rêgem laudant.
  The farmers are praising the king. 
 
Rêgês videt três.
  She sees three kings.

Ablative

The "by-with-from case": Certain prepositions and certain verbs govern objects in this case. Used alone it can have an adverbial meaning, for example, to indicate by what means something is done.

-E;

-IBUS

rêge, rêgibus

 rêge litterae scrîptae sunt.
  The letter was written by the king.
 
Dê rêgibus multa scrîpsit hic auctor.
  This author wrote many things about kings.