Latin has seven different noun cases: nominative, vocative, accusative, genitive, dative, ablative and locative. The vocative case is almost always the same as the nominative case; however, if the nominative ends in -us, it changes to -e, and if the nominative ends in -ius, it changes to -i. The locative takes the form of the dative. Latin nouns are "declined", or changed, according to how they are used in the sentence. A noun can be declined five different ways. These ways are called declensions. The declensions are numbered 1 through 5 (first declension, second declension etc), each having different endings that identify the noun's declension. When a noun is declined, twelve forms are made, two for each of the noun cases (the locative is omitted).